Journal of Physics D: Applied Physics - IOPscience

Journal of Physics D: Applied Physics - IOPscience
Journal of Physics D: Applied Physics
Purpose-led Publishing
is a coalition of three not-for-profit publishers in the field of physical sciences: AIP Publishing, the American Physical Society and IOP Publishing.
Together, as publishers that will always put purpose above profit, we have defined a set of industry standards that underpin high-quality, ethical scholarly communications.
We are proudly declaring that science is our only shareholder.
SUPPORTS OPEN ACCESS
An international journal publishing high quality work concerned with all aspects of applied physics research, from biophysics, magnetism, plasmas, semiconductors, energy materials and devices to the structure and properties of matter.
Submit
an article
opens in new tab
Track my article
opens in new tab
RSS
Sign up for new issue notifications
Median submission to first decision before peer review
6 days
Median submission to first decision after peer review
44 days
Impact factor
3.2
Citescore
6.4
Full list of journal metrics
The following article is
Open access
The 2026 guided acoustic waves roadmap
Hubert J Krenner
et al
2026
J. Phys. D: Appl. Phys.
59
093001
View article
, The 2026 guided acoustic waves roadmap
PDF
, The 2026 guided acoustic waves roadmap
Guided elastic waves are a truly cross-disciplinary key enabling technology. For more than five decades, surface acoustic wave (SAW) and bulk acoustic wave devices find widespread applications. Nowadays, different types of guided elastic waves cover the wide spectrum of applications spanning from quantum technologies to the life sciences, from controlling single excitations to macroscopic collective states in condensed matter. Six years after the first 2019 SAW roadmap, we believe it is time to make a step back and take a fresh look at the status of the field and its future challenges. Since the first roadmap in 2019, the spectrum clearly expanded and this new edition presents a current snapshot of the status of this vibrant field and prospects for potential future developments.
The following article is
Open access
The 2022 Plasma Roadmap: low temperature plasma science and technology
I Adamovich
et al
2022
J. Phys. D: Appl. Phys.
55
373001
View article
, The 2022 Plasma Roadmap: low temperature plasma science and technology
PDF
, The 2022 Plasma Roadmap: low temperature plasma science and technology
The 2022 Roadmap is the next update in the series of Plasma Roadmaps published by
Journal of Physics
D with the intent to identify important outstanding challenges in the field of low-temperature plasma (LTP) physics and technology. The format of the Roadmap is the same as the previous Roadmaps representing the visions of 41 leading experts representing 21 countries and five continents in the various sub-fields of LTP science and technology. In recognition of the evolution in the field, several new topics have been introduced or given more prominence. These new topics and emphasis highlight increased interests in plasma-enabled additive manufacturing, soft materials, electrification of chemical conversions, plasma propulsion, extreme plasma regimes, plasmas in hypersonics, data-driven plasma science and technology and the contribution of LTP to combat COVID-19. In the last few decades, LTP science and technology has made a tremendously positive impact on our society. It is our hope that this roadmap will help continue this excellent track record over the next 5–10 years.
The following article is
Open access
The 2023 terahertz science and technology roadmap
Alfred Leitenstorfer
et al
2023
J. Phys. D: Appl. Phys.
56
223001
View article
, The 2023 terahertz science and technology roadmap
PDF
, The 2023 terahertz science and technology roadmap
Terahertz (THz) radiation encompasses a wide spectral range within the electromagnetic spectrum that extends from microwaves to the far infrared (100 GHz–∼30 THz). Within its frequency boundaries exist a broad variety of scientific disciplines that have presented, and continue to present, technical challenges to researchers. During the past 50 years, for instance, the demands of the scientific community have substantially evolved and with a need for advanced instrumentation to support radio astronomy, Earth observation, weather forecasting, security imaging, telecommunications, non-destructive device testing and much more. Furthermore, applications have required an emergence of technology from the laboratory environment to production-scale supply and in-the-field deployments ranging from harsh ground-based locations to deep space. In addressing these requirements, the research and development community has advanced related technology and bridged the transition between electronics and photonics that high frequency operation demands. The multidisciplinary nature of THz work was our stimulus for creating the 2017 THz Science and Technology Roadmap (Dhillon
et al
2017
J. Phys. D: Appl. Phys.
50
043001). As one might envisage, though, there remains much to explore both scientifically and technically and the field has continued to develop and expand rapidly. It is timely, therefore, to revise our previous roadmap and in this 2023 version we both provide an update on key developments in established technical areas that have important scientific and public benefit, and highlight new and emerging areas that show particular promise. The developments that we describe thus span from fundamental scientific research, such as THz astronomy and the emergent area of THz quantum optics, to highly applied and commercially and societally impactful subjects that include 6G THz communications, medical imaging, and climate monitoring and prediction. Our Roadmap vision draws upon the expertise and perspective of multiple international specialists that together provide an overview of past developments and the likely challenges facing the field of THz science and technology in future decades. The document is written in a form that is accessible to policy makers who wish to gain an overview of the current state of the THz art, and for the non-specialist and curious who wish to understand available technology and challenges. A such, our experts deliver a ‘snapshot’ introduction to the current status of the field and provide suggestions for exciting future technical development directions. Ultimately, we intend the Roadmap to portray the advantages and benefits of the THz domain and to stimulate further exploration of the field in support of scientific research and commercial realisation.
The following article is
Open access
The 2026 active metamaterials roadmap
Simon A Pope
et al
2026
J. Phys. D: Appl. Phys.
59
143001
View article
, The 2026 active metamaterials roadmap
PDF
, The 2026 active metamaterials roadmap
Active metamaterials (AMMs) are engineered structures that possess novel properties that can be changed after the point of manufacture. Their novel properties arise predominantly from their physical structure, as opposed to their chemical composition and can be changed through means such as direct energy addition into wave paths, or physically changing/morphing the structure in response to both a user or environmental input. AMMs are currently of wide interest to the physics community and encompass a range of sub-domains in applied physics (e.g. photonic, microwave, acoustic, mechanical, etc). They possess the potential to provide solutions that are more suitable to specific applications, or which allow novel properties to be produced which cannot be achieved with passive metamaterials, such as time-varying or gain enhancement effects. They have the potential to help solve some of the important current and future problems faced by the advancement of modern society, such as achieving net-zero, sustainability, healthcare and equality goals. Despite their huge potential, the added complexity of their design and operation, compared to passive metamaterials creates challenges to the advancement of the field, particularly beyond theoretical and lab-based experiments. This roadmap brings together experts in all types of AMMs and across a wide range of areas of applied physics. The objective is to provide an overview of the current state of the art and the associated current/future challenges, with the hope that the required advances identified create a roadmap for the future advancement and application of this field.
The following article is
Open access
The 2017 terahertz science and technology roadmap
S S Dhillon
et al
2017
J. Phys. D: Appl. Phys.
50
043001
View article
, The 2017 terahertz science and technology roadmap
PDF
, The 2017 terahertz science and technology roadmap
Science and technologies based on terahertz frequency electromagnetic radiation (100 GHz–30 THz) have developed rapidly over the last 30 years. For most of the 20th Century, terahertz radiation, then referred to as sub-millimeter wave or far-infrared radiation, was mainly utilized by astronomers and some spectroscopists. Following the development of laser based terahertz time-domain spectroscopy in the 1980s and 1990s the field of THz science and technology expanded rapidly, to the extent that it now touches many areas from fundamental science to ‘real world’ applications. For example THz radiation is being used to optimize materials for new solar cells, and may also be a key technology for the next generation of airport security scanners. While the field was emerging it was possible to keep track of all new developments, however now the field has grown so much that it is increasingly difficult to follow the diverse range of new discoveries and applications that are appearing. At this point in time, when the field of THz science and technology is moving from an emerging to a more established and interdisciplinary field, it is apt to present a roadmap to help identify the breadth and future directions of the field. The aim of this roadmap is to present a snapshot of the present state of THz science and technology in 2017, and provide an opinion on the challenges and opportunities that the future holds. To be able to achieve this aim, we have invited a group of international experts to write 18 sections that cover most of the key areas of THz science and technology. We hope that The 2017 Roadmap on THz science and technology will prove to be a useful resource by providing a wide ranging introduction to the capabilities of THz radiation for those outside or just entering the field as well as providing perspective and breadth for those who are well established. We also feel that this review should serve as a useful guide for government and funding agencies.
The following article is
Open access
The 2018 GaN power electronics roadmap
H Amano
et al
2018
J. Phys. D: Appl. Phys.
51
163001
View article
, The 2018 GaN power electronics roadmap
PDF
, The 2018 GaN power electronics roadmap
Gallium nitride (GaN) is a compound semiconductor that has tremendous potential to facilitate economic growth in a semiconductor industry that is silicon-based and currently faced with diminishing returns of performance versus cost of investment. At a material level, its high electric field strength and electron mobility have already shown tremendous potential for high frequency communications and photonic applications. Advances in growth on commercially viable large area substrates are now at the point where power conversion applications of GaN are at the cusp of commercialisation. The future for building on the work described here in ways driven by specific challenges emerging from entirely new markets and applications is very exciting. This collection of GaN technology developments is therefore not itself a road map but a valuable collection of global state-of-the-art GaN research that will inform the next phase of the technology as market driven requirements evolve. First generation production devices are igniting large new markets and applications that can only be achieved using the advantages of higher speed, low specific resistivity and low saturation switching transistors. Major investments are being made by industrial companies in a wide variety of markets exploring the use of the technology in new circuit topologies, packaging solutions and system architectures that are required to achieve and optimise the system advantages offered by GaN transistors. It is this momentum that will drive priorities for the next stages of device research gathered here.
The following article is
Open access
An overview of phase-change memory device physics
Manuel Le Gallo and Abu Sebastian 2020
J. Phys. D: Appl. Phys.
53
213002
View article
, An overview of phase-change memory device physics
PDF
, An overview of phase-change memory device physics
Phase-change memory (PCM) is an emerging non-volatile memory technology that has recently been commercialized as storage-class memory in a computer system. PCM is also being explored for non-von Neumann computing such as in-memory computing and neuromorphic computing. Although the device physics related to the operation of PCM have been widely studied since its discovery in the 1960s, there are still several open questions relating to their electrical, thermal, and structural dynamics. In this article, we provide an overview of the current understanding of the main PCM device physics that underlie the read and write operations. We present both experimental characterization of the various properties investigated in nanoscale PCM devices as well as physics-based modeling efforts. Finally, we provide an outlook on some remaining open questions and possible future research directions.
The following article is
Open access
Thermal management and packaging of wide and ultra-wide bandgap power devices: a review and perspective
Yuan Qin
et al
2023
J. Phys. D: Appl. Phys.
56
093001
View article
, Thermal management and packaging of wide and ultra-wide bandgap power devices: a review and perspective
PDF
, Thermal management and packaging of wide and ultra-wide bandgap power devices: a review and perspective
Power semiconductor devices are fundamental drivers for advances in power electronics, the technology for electric energy conversion. Power devices based on wide-bandgap (WBG) and ultra-wide bandgap (UWBG) semiconductors allow for a smaller chip size, lower loss and higher frequency compared with their silicon (Si) counterparts, thus enabling a higher system efficiency and smaller form factor. Amongst the challenges for the development and deployment of WBG and UWBG devices is the efficient dissipation of heat, an unavoidable by-product of the higher power density. To mitigate the performance limitations and reliability issues caused by self-heating, thermal management is required at both device and package levels. Packaging in particular is a crucial milestone for the development of any power device technology; WBG and UWBG devices have both reached this milestone recently. This paper provides a timely review of the thermal management of WBG and UWBG power devices with an emphasis on packaged devices. Additionally, emerging UWBG devices hold good promise for high-temperature applications due to their low intrinsic carrier density and increased dopant ionization at elevated temperatures. The fulfillment of this promise in system applications, in conjunction with overcoming the thermal limitations of some UWBG materials, requires new thermal management and packaging technologies. To this end, we provide perspectives on the relevant challenges, potential solutions and research opportunities, highlighting the pressing needs for device–package electrothermal co-design and high-temperature packages that can withstand the high electric fields expected in UWBG devices.
The following article is
Open access
The 2020 plasma catalysis roadmap
Annemie Bogaerts
et al
2020
J. Phys. D: Appl. Phys.
53
443001
View article
, The 2020 plasma catalysis roadmap
PDF
, The 2020 plasma catalysis roadmap
Plasma catalysis is gaining increasing interest for various gas conversion applications, such as CO
conversion into value-added chemicals and fuels, CH
activation into hydrogen, higher hydrocarbons or oxygenates, and NH
synthesis. Other applications are already more established, such as for air pollution control, e.g. volatile organic compound remediation, particulate matter and NO
removal. In addition, plasma is also very promising for catalyst synthesis and treatment. Plasma catalysis clearly has benefits over ‘conventional’ catalysis, as outlined in the Introduction. However, a better insight into the underlying physical and chemical processes is crucial. This can be obtained by experiments applying diagnostics, studying both the chemical processes at the catalyst surface and the physicochemical mechanisms of plasma-catalyst interactions, as well as by computer modeling. The key challenge is to design cost-effective, highly active and stable catalysts tailored to the plasma environment. Therefore, insight from thermal catalysis as well as electro- and photocatalysis is crucial. All these aspects are covered in this Roadmap paper, written by specialists in their field, presenting the state-of-the-art, the current and future challenges, as well as the advances in science and technology needed to meet these challenges.
The following article is
Open access
The 2021 battery technology roadmap
Jianmin Ma
et al
2021
J. Phys. D: Appl. Phys.
54
183001
View article
, The 2021 battery technology roadmap
PDF
, The 2021 battery technology roadmap
Sun, wind and tides have huge potential in providing us electricity in an environmental-friendly way. However, its intermittency and non-dispatchability are major reasons preventing full-scale adoption of renewable energy generation. Energy storage will enable this adoption by enabling a constant and high-quality electricity supply from these systems. But which storage technology should be considered is one of important issues. Nowadays, great effort has been focused on various kinds of batteries to store energy, lithium-related batteries, sodium-related batteries, zinc-related batteries, aluminum-related batteries and so on. Some cathodes can be used for these batteries, such as sulfur, oxygen, layered compounds. In addition, the construction of these batteries can be changed into flexible, flow or solid-state types. There are many challenges in electrode materials, electrolytes and construction of these batteries and research related to the battery systems for energy storage is extremely active. With the myriad of technologies and their associated technological challenges, we were motivated to assemble this 2020 battery technology roadmap.
Study of dark zone phenomenon of three-electrode dielectric barrier discharge
Qiaojue Liu
et al
2026
J. Phys. D: Appl. Phys.
59
165203
View article
, Study of dark zone phenomenon of three-electrode dielectric barrier discharge
PDF
, Study of dark zone phenomenon of three-electrode dielectric barrier discharge
Dielectric barrier discharge (DBD) has promising applications in aircraft anti-icing and de-icing due to plasma thermal effects, while enabling active flow control in specific topologies. This study pioneers the investigation of dark zone phenomena in a three-electrode DBD configuration featuring a suspension electrode—a critical distinction beyond conventional DBD system. Experimental results revealed that dark zone phenomenon would be appeared when the suspension electrode covered a certain number of buried electrodes, or was laid in a small range before and after the corresponding position. Quantitative analysis enabled classification of discharge suppression into two mechanistic modes: strong suppression mode and weak suppression mode. Theoretical modeling demonstrated that the local dark zone mechanism was attributed to the superposition of electric fields between electrodes. This fundamental understanding establishes a predictive framework for discharge pattern in multi-electrode plasma systems. The proposed dark zone regulation theory can also facilitate further applications in fields such as anti-icing and de-icing, material modification.
The following article is
Open access
Interpolation-based data augmentation for film thickness regression in atmospheric pressure plasma jet deposition via optical emission spectroscopy
Jia-He Tee
et al
2026
J. Phys. D: Appl. Phys.
59
165205
View article
, Interpolation-based data augmentation for film thickness regression in atmospheric pressure plasma jet deposition via optical emission spectroscopy
PDF
, Interpolation-based data augmentation for film thickness regression in atmospheric pressure plasma jet deposition via optical emission spectroscopy
Advancements in artificial intelligence have facilitated the widespread application of machine learning techniques in industrial, manufacturing, and scientific domains. However, the scarcity of labeled data continues to pose a major challenge for effective analysis and modeling. To address this limitation, we propose an interpolation-based data augmentation method that generates pseudo-labeled data points between sparsely labeled sequences. Time-series spectral data acquired during atmospheric pressure plasma jet thin film deposition are used to interpolate labels for intermediate data points based on feature similarity and temporal order, thereby generating additional training data with estimated labels. We evaluated data augmentation across multiple cycles on three representative regression models, i.e. Lasso, multilayer perceptron (MLP), and extreme gradient boosting, and found that the implementation of data augmentation effectively reduced the mean absolute error (MAE) and mean absolute percentage error (MAPE) in film thickness prediction. In particular, with four augmentation cycles, the MLP achieved the greatest improvement, reducing MAE by 5.5% and MAPE by 16.5% compared with the baseline without augmentation. In addition to improving prediction accuracy, we further examined model robustness, which is quantitatively defined as the relative percentage change in prediction error when outliers are introduced. Under this definition, the proposed augmentation method enhances robustness by mitigating the adverse effects of outlier datasets. These findings demonstrate the effectiveness of the method for regression on sequential process data, particularly under conditions of limited labeled data and the presence of outliers.
Genetic algorithm guided design of gradient multilayer metamaterial for ultra broadband and wide angle electromagnetic wave absorption
Yinhui Xue
et al
2026
J. Phys. D: Appl. Phys.
59
165302
View article
, Genetic algorithm guided design of gradient multilayer metamaterial for ultra broadband and wide angle electromagnetic wave absorption
PDF
, Genetic algorithm guided design of gradient multilayer metamaterial for ultra broadband and wide angle electromagnetic wave absorption
This paper presents a genetic algorithm-driven design of a gradient multilayer pyramid metamaterial absorber for ultra broadband and wide-angle electromagnetic wave absorption. The proposed structure evolves from a conventional stepped pyramid into an optimized five-layer frustum configuration, enabling continuous impedance matching across a broad frequency range. Under normal incidence, the absorber based on composite comprising carbonyl iron particles (CIP) and polyamide achieves an effective absorption bandwidth spanning 2.8–40 GHz, corresponding to a relative bandwidth of 173.8%. Angularly, it maintains stable performance for wide incident angles up to 60°. The broadband and angularly robust absorption is attributed to complementary layer-wise impedance matching and spatially distributed dissipation mechanisms. Full-wave simulations, supported by experimental validation using 3D-printed samples, confirm the design’s effectiveness and manufacturability. Radar cross section analysis further indicates significant scattering reduction, highlighting its potential in practical applications such as radar stealth, camouflage, and electromagnetic interference shielding.
The influence of ion energy distribution in plasma-enhanced chemical vapor deposition on the sp
/sp
ratio of diamond-like carbon
Junping Zhao
et al
2026
J. Phys. D: Appl. Phys.
59
165202
View article
, The influence of ion energy distribution in plasma-enhanced chemical vapor deposition on the sp3/sp2 ratio of diamond-like carbon
PDF
, The influence of ion energy distribution in plasma-enhanced chemical vapor deposition on the sp3/sp2 ratio of diamond-like carbon
Due to the outstanding thermal and electrical properties of diamond-like carbon (DLC), a strategy for fabricating high thermal conductivity epoxy composites through surface modification of filler particles via DLC deposition has been developed. However, a key challenge remains: the ion energy in the plasma-enhanced chemical vapor deposition used for particle modification exhibits a broad distribution, and the synergistic effects of ions with different energies on the sp
/sp
ratio of DLC are still not well understood. In this study, the ion energy distributions under various voltage conditions were experimentally measured, and the evolution of the sp
/sp
ratio in DLC films deposited on alumina particles was systematically characterised. The results indicate that the the sp
/sp
ratio of DLC arises from the collective contribution of ions across multiple energy levels, though their individual influences vary significantly. Notably, ions within the 100 ∼ 200 eV energy range exhibit the greatest positive impact on enhancing the sp
/sp
ratio. By integrating molecular dynamics simulations to capture the dynamic behavior of ions during the deposition process, a novel evaluation approach was proposed—assessing the influence of ion energy distribution on the sp
/sp
ratio through the number density of ‘extra atoms’ introduced into the DLC network by ion implantation. This method enables direct prediction of the sp
/sp
ratio trend based solely on ion energy distribution characteristics, offering a rational and efficient pathway for optimizing deposition parameters. It holds significant practical value for advancing the scalability and controllability of plasma-based surface modification technologies.
Research on the dominant species of the reduced ionization coefficient
and the reduced attachment coefficient
η/N
and the dielectric breakdown properties of hot C
N–CO
–O
gas mixtures
Lifan Zhang
et al
2026
J. Phys. D: Appl. Phys.
59
165204
View article
, Research on the dominant species of the reduced ionization coefficient α/N and the reduced attachment coefficient η/N and the dielectric breakdown properties of hot C4F7N–CO2–O2 gas mixtures
PDF
, Research on the dominant species of the reduced ionization coefficient α/N and the reduced attachment coefficient η/N and the dielectric breakdown properties of hot C4F7N–CO2–O2 gas mixtures
N–CO
gas mixtures have attracted considerable interest attention as promising insulating and arc-quenching media to replace SF
. Research indicates that adding O
can alleviate or even prevent solid carbon condensation during the operation of C
N–CO
gas mixtures. However, the introduction of O
also complicates the high-temperature chemical species composition of the gas mixture, which would influence its dielectric breakdown performance. Research on the hot dielectric breakdown properties of C
N–CO
–O
gas mixtures remains scarce. In this work, the virtual gas method (VGM) is employed as a systematic analysis tool. This method defines a weight to quantitatively rank the influence of each constituent species on the reduced ionization coefficient
and reduced attachment coefficient
, thereby identifying the dominant species and clarifying their mechanistic roles. It further elucidates how these species affect the hot dielectric breakdown properties. To validate the VGM, the dominant species of
and
in two SF
–CO
gas mixtures were first investigated. Favorable comparison with published literature confirmed the method’s effectiveness. The study then investigated a wide range of C
N–CO
–O
gas mixtures relevant to medium-voltage switchgear applications at 0.1 MPa, with C
N and O
mixing ratios of 5%–30% and 0%–30%, respectively. Application of the VGM revealed the dominant species in the ionization and attachment processes, as well as those that critically influence the critical reduced breakdown field strength
. Results show that below 1000 K, CO
and CF
are the dominant species, and the
increases with a higher O
mixing ratio due to solid carbon formation. Above 2000 K, the
varies significantly with the C
N mixing ratio because mixtures with higher mole fractions of CF
and CF exhibit a higher
. Notably, in mixtures with a high proportion of C
N, increased O
content leads to more pronounced degradation of hot dielectric breakdown properties between 2000 K and 4000 K. This study provides fundamental data for modeling post-arc dielectric recovery in medium-voltage switchgear and offers practical guidance for optimizing the mixing ratios of C
N–CO
–O
gas mixtures. Furthermore, the insights into dominant species provide guidance for the molecular design of environmentally friendly insulating and arc-quenching media with high hot-dielectric strength.
Terahertz metasurface sensor and its applications
Zeyu Hou
et al
2026
J. Phys. D: Appl. Phys.
59
163001
View article
, Terahertz metasurface sensor and its applications
PDF
, Terahertz metasurface sensor and its applications
Terahertz waves, often referred to as far-infrared radiation, represent a unique band of high-frequency electromagnetic waves. In biosensing applications, terahertz waves possess extremely low photon energies—much lower than those of visible and near-infrared radiation—thereby ensuring the safety of biological detection. At the same time, their frequency range covers the characteristic spectral regions associated with collective vibrational modes and weak intermolecular interactions of biological macromolecules. In addition, terahertz waves exhibit strong penetrability through dielectric materials, and a single terahertz pulse can span an ultrabroad bandwidth ranging from the gigahertz to tens of terahertz. When integrated with metasurfaces, terahertz metasurface sensors can further enhance local electric fields, suppress background noise and interference, significantly improve the detection sensitivity, and enable high-sensitivity quantitative analysis of trace biomolecules. This review provides a comprehensive overview of terahertz metasurface sensors from multiple perspectives. It covers terahertz refractive index sensors based on various operating principles, metasurfaces fabricated from different materials—including metallic structures, doped semiconductors, and all-dielectric components—as well as hybrid designs incorporating two-dimensional materials like graphene. The article further categorizes sensors based on their specific application targets. Furthermore, it examines the different device architectures and modulation principles employed, analyzing their respective advantages, drawbacks, and future development trajectories.
The following article is
Open access
Molecular lithography with DNA nanostructures: methods and applications
Adrian Keller and Veikko Linko 2026
J. Phys. D: Appl. Phys.
59
153001
View article
, Molecular lithography with DNA nanostructures: methods and applications
PDF
, Molecular lithography with DNA nanostructures: methods and applications
Lithographic surface patterning is a cornerstone of modern materials and device fabrication. Although the available lithography techniques are constantly being advanced to push the feature sizes down to the few-nanometer scale, such developments are associated with many technological and economic challenges. Combining established top–down lithography with bottom-up self-assembly strategies has the potential to overcome those challenges and enable the manipulation of matter with molecular precision. One of the most exciting approaches in this regard is to harness the programmability of DNA self-assembly to create precise DNA nanostructure masks to be used in the lithographic patterning of diverse substrates. DNA nanotechnology has provided us with a versatile toolbox for the high-yield synthesis of 2D and 3D nanostructures with complex, user-defined shapes at unprecedented molecular accuracy. Consequently, the last decade has seen intense research efforts aimed at transferring such DNA nanostructure shapes into functional organic and inorganic materials and we have now arrived at a point where sophisticated molecular lithography approaches utilize DNA nanostructure masks for the fabrication of plasmonic surfaces for metamaterials and sensing applications. This review summarizes how the spatial information of such DNA nanostructure masks can be transferred into various organic and inorganic materials through selective etching and deposition steps. The review also discusses recent developments toward all-purpose molecular lithography schemes and highlights promising extensions of the discussed methods toward new materials systems and application fields.
The following article is
Open access
The 2026 active metamaterials roadmap
Simon A Pope
et al
2026
J. Phys. D: Appl. Phys.
59
143001
View article
, The 2026 active metamaterials roadmap
PDF
, The 2026 active metamaterials roadmap
Active metamaterials (AMMs) are engineered structures that possess novel properties that can be changed after the point of manufacture. Their novel properties arise predominantly from their physical structure, as opposed to their chemical composition and can be changed through means such as direct energy addition into wave paths, or physically changing/morphing the structure in response to both a user or environmental input. AMMs are currently of wide interest to the physics community and encompass a range of sub-domains in applied physics (e.g. photonic, microwave, acoustic, mechanical, etc). They possess the potential to provide solutions that are more suitable to specific applications, or which allow novel properties to be produced which cannot be achieved with passive metamaterials, such as time-varying or gain enhancement effects. They have the potential to help solve some of the important current and future problems faced by the advancement of modern society, such as achieving net-zero, sustainability, healthcare and equality goals. Despite their huge potential, the added complexity of their design and operation, compared to passive metamaterials creates challenges to the advancement of the field, particularly beyond theoretical and lab-based experiments. This roadmap brings together experts in all types of AMMs and across a wide range of areas of applied physics. The objective is to provide an overview of the current state of the art and the associated current/future challenges, with the hope that the required advances identified create a roadmap for the future advancement and application of this field.
The following article is
Open access
Theory of tunneling magnetoresistance
X-G Zhang and Mairbek Chshiev 2026
J. Phys. D: Appl. Phys.
59
143002
View article
, Theory of tunneling magnetoresistance
PDF
, Theory of tunneling magnetoresistance
This review is an account of theory of spin-dependent tunneling and magnetoresistive transport in magnetic tunnel junctions, covering coherent and incoherent tunneling processes, first-principles theory, and device-level phenomena. We begin with early theories predating the Fe-MgO-Fe era, then proceed to the symmetry-filtered tunneling through crystalline MgO barriers, where the Δ
band of bcc ferromagnets enables nearly perfect spin selectivity. The dependence of tunneling magnetoresistance (TMR) on interfacial chemistry, atomic order, and electrode symmetry is discussed in connection with both experimental observations and electronic structure calculations. Alternative barriers, including spinel oxides, ferroelectric oxides, and two-dimensional materials, are surveyed with attention to their spin-filtering efficiency, electronic compatibility, and structural tunability. Beyond coherent tunneling, we also cover theoretical models for nonspecular and inelastic scattering inside the barrier. We explain several persistent discrepancies between theory and experiment—such as the reduced antiparallel resistance and oscillatory TMR by showing how diffuse scattering equalizes the decay of all evanescent states. Inelastic effects from magnons and magnetic impurities offer additional spin–flip channels that degrade TMR with increasing bias or temperature, providing a microscopic interpretation of zero-bias anomalies and magnon-assisted tunneling. First-principles modeling, particularly density functional theory combined with nonequilibrium Green’s functions, enables quantitative simulation of spin-dependent transport under finite bias. The emerging steady-state density functional framework further generalizes this to strongly nonequilibrium conditions. Finally, the review connects microscopic tunneling physics with the macroscopic behavior of spin-transfer torque and spin–orbit torque magnetic random-access memories. Through this synthesis, we highlight the underlying principles: symmetry, scattering, and spin–orbit coupling that unify diverse material systems and device concepts. The goal is to provide both a coherent conceptual framework and a roadmap linking fundamental spin-dependent tunneling mechanisms to practical spintronic technologies.
The following article is
Open access
Mitigating sidewall damage effects in GaN-based multi-quantum-well micro-LEDs prepared by top–down fabrication
In-Hwan Lee
et al
2026
J. Phys. D: Appl. Phys.
59
133004
View article
, Mitigating sidewall damage effects in GaN-based multi-quantum-well micro-LEDs prepared by top–down fabrication
PDF
, Mitigating sidewall damage effects in GaN-based multi-quantum-well micro-LEDs prepared by top–down fabrication
This review examines the sidewall damage effects in GaN-based micro- and nano-light emitting diodes (
LEDs/nLEDs) fabricated via top–down inductively coupled plasma reactive ion etching. We analyze the structural and electronic properties of etched surfaces, damage mitigation strategies through process optimization, and postetch treatments. Furthermore, we evaluate models explaining performance degradation with a decrease in device dimensions. Blue InGaN/GaN
LEDs exhibit severe efficiency degradation below ∼20
m diameter (the ‘efficiency cliff’), whereas green and red devices show greater resilience. We attribute this behavior to differences in surface recombination velocity, carrier diffusion length, and localization effects. Surface treatments including tetramethylammonium hydroxide etching, (NH
S passivation, hydrogen plasma treatment, and atomic layer–deposited dielectrics significantly mitigate damage. Deep-level transient spectroscopy reveals nitrogen interstitial (N
) acceptors near
-1 eV and gallium vacancy (V
Ga
) complexes near
+ 0.8 eV as the dominant recombination centers. The damaged region extends 0.5–1
m from sidewalls—significantly beyond the structurally damaged zone (∼40–100 nm). Emerging approaches, such as neutral beam etching and localized surface plasmon coupling, show promise for achieving high efficiency in sub-5
m devices required for advanced display applications.
Hybrid simulation of the bias effect on inductively coupled C
/Ar plasmas
Li et al
View accepted manuscript
, Hybrid simulation of the bias effect on inductively coupled C4F8/Ar plasmas
PDF
, Hybrid simulation of the bias effect on inductively coupled C4F8/Ar plasmas
To independently control the ion flux and ion energy in inductively coupled plasmas, a bias source is usually applied to the substrate. In this work, a hybrid model, which consists of a global model, a fluid sheath model, and an ion Monte Carlo collision (MCC) model is developed, to systematically investigate the influence of the bias voltage on the particle density in C₄F₈/Ar plasmas under various pressures.Furthermore, a multi-harmonic-superimposed sawtooth bias waveform is proposed for precise modulation of the ion energy distribution function (IEDF). The results show that at 30 mTorr, CF₄ is the main fluorocarbon species, with its density varying non-monotonically with bias voltage. CF₃⁺ density is higher than the other positive ions above 100 V, and electrons are the primary negative charge carriers above 400 V. As pressure rises to 100 mTorr, although the behavior of positive ions with bias voltage is similar to that at 30 mTorr, their proportions are different. Besides, CF₃⁻ shows a considerable enhancement at this higher pressure, and becomes the predominant negative ion within the investigated bias voltages. Additionally, by introducing more high order harmonics in the bias voltage waveform, the ion energy separation width becomes narrower. Especially for C₂F₄⁺, the IEDF at low bias voltage shifts from a bimodal structure at N = 1 to a unimodal distribution at N = 20. This is because ions are not able to respond to the rapid oscillation of the sheath due to their low velocity. The results obtained in this work demonstrate that in C₄F₈/Ar plasmas, the regulation of bias voltage enables effective control over the generation of active species and the ion energy distribution, which is critical for optimizing etching processes.
Review on ultrathin-barrier AlGaN(<6 nm)/GaN enhancement-mode technology: concept, device fabrication, and integration prospects
Huang et al
View accepted manuscript
, Review on ultrathin-barrier AlGaN(<6 nm)/GaN enhancement-mode technology: concept, device fabrication, and integration prospects
PDF
, Review on ultrathin-barrier AlGaN(<6 nm)/GaN enhancement-mode technology: concept, device fabrication, and integration prospects
With the growing demand for high-efficiency, highly integrated, and highly reliable devices in power electronics and radio frequency (RF) systems, gallium nitride (GaN)-based high electron mobility transistors (HEMTs) technology has advanced rapidly. Traditional enhancement-mode (E-mode) GaN devices typically rely on processes such as gate trench etching, fluoride ion implantation, or p-GaN gates, which suffer from poor etch uniformity, threshold voltage instability, and low yield rates. The ultrathin barrier (UTB) AlGaN/GaN heterostructure, owing to its inherent depletion of the two-dimensional electron gas (2DEG), has emerged as an ideal platform for realizing trenchless enhancement-mode devices. This paper systematically reviews the current development status of UTB AlGaN/GaN enhancement-mode MIS-HEMT technology, focusing on its operating principles, key processes (such as low-resistance ohmic contacts and high-reliability gate dielectrics), device performance enhancements (including power and RF performance), and its application prospects in E/D-mode co-integration and RF-power synergistic integration. The article concludes by discussing the challenges UTB technology faces during large-scale industrialization, such as interface defect control, wafer-level uniformity, and thermal management, while also proposing potential solutions and prospects. The UTB GaN technology provides a robust foundation for realizing high-performance, highly uniform, and CMOS-compatible GaN power and RF system-on-chip (SoC) solutions.
Antiferromagnetism with an elevated Néel temperature in Janus FeXF (X = O, S) monolayers
Zhang et al
View accepted manuscript
, Antiferromagnetism with an elevated Néel temperature in Janus FeXF (X = O, S) monolayers
PDF
, Antiferromagnetism with an elevated Néel temperature in Janus FeXF (X = O, S) monolayers
Inspired by the recently synthesized hexagonal layered phase of FeF
, we studied the magnetic properties of the 1T-FeF
monolayer and its Janus FeXF (X = O, S) derivatives by first-principles calculations. Our results confirm that these materials are antiferromagnetic semiconductors, and that anion substitution effectively tunes their material properties: the band gap shifts from 3.37 eV (direct, FeF 2 ) to 2.35 eV (direct, FeOF) and 1.13 eV (indirect, FeSF); the magnetic moment of Fe ions increases; and the Néel temperature (T
) rises dramatically to 248 K (FeSF) and 207 K (FeOF). Janus structures exhibit enhanced magnetic moment and direct AFM coupling. Under modest compressive strain, T
can be further enhanced to 274 K (-2% strain, FeSF) and 244 K (-5% strain, FeOF), with the former approaching room temperature. Both Janus materials retain their semiconducting nature and direction of easy magnetization axis under ±5% strain. This study validates the Janus structure as a viable approach to enhance 2D antiferromagnetism and highlights Fe-based oxyhalides as promising spintronic materials.
Cold atmospheric plasma mediated selective cytotoxicity against glioma cells: A comprehensive analysis of cellular reactive oxygen species generation pathways
Luo et al
View accepted manuscript
, Cold atmospheric plasma mediated selective cytotoxicity against glioma cells: A comprehensive analysis of cellular reactive oxygen species generation pathways
PDF
, Cold atmospheric plasma mediated selective cytotoxicity against glioma cells: A comprehensive analysis of cellular reactive oxygen species generation pathways
Cold atmospheric plasma (CAP) has emerged as a promising therapeutic strategy for tumors, exerting anti-tumor effects primarily via reactive oxygen species (ROS)-mediated cytotoxicity that disrupts tumor cell redox homeostasis. This process is based on plasma-liquid interaction. Gaseous ROS from the plasma plume form water-soluble ROS in the liquid medium, which mediate intracellular ROS accumulation. While this selective cytotoxicity toward tumor cells is well-documented, the contributions of exogenous/endogenous ROS generation and clearance mechanisms to the differential responsiveness of tumor versus normal cells to CAP remain elusive. Here, we used human glioma U251 cells and normal astrocyte HA1800 cells as cellular models to systematically elucidate the underlying molecular mechanisms by inhibiting distinct ROS production and clearance pathways. Our results demonstrated that in U251 cells, exogenous ROS influx via aquaporin-mediated transport and cell membrane oxidative damage, combined with endogenous ROS generation through the mitochondrial and NADPH oxidase 1/4 pathways, collectively represented the core mechanism driving intracellular ROS accumulation. Notably, catalase served as the primary mediator of intracellular ROS clearance in U251 cells. In contrast, HA1800 cells exhibited distinct ROS production and clearance profiles, which underpinned the selective tumoricidal activity of CAP against glioma cells. Collectively, our findings confirm that CAP promotes exogenous ROS influx and endogenous ROS generation, while modulating the antioxidant defense system through multiple pathways, thereby inducing selective functional impairment in glioma cells. This study clarifies the mechanistic basis of CAP-mediated anti-tumor activity and provides preclinical evidence supporting the potential clinical application of CAP for glioma therapy.
All-dielectric metasurface diffractive neural network for multi-class recognition via binary coding of detection regions
sun et al
View accepted manuscript
, All-dielectric metasurface diffractive neural network for multi-class recognition via binary coding of detection regions
PDF
, All-dielectric metasurface diffractive neural network for multi-class recognition via binary coding of detection regions
As an emerging optical machine learning architecture, the diffractive deep neural network (D2NN) has attracted considerable attention owing to its low energy consumption, parallel processing capability, and high speed. Here, we proposed a D2NN logic-encoding scheme based on metasurfaces, wherein binary coding rules are applied to the detection regions in the output plane, thereby enhancing the spatial utilization of the output layer and increasing the number of recognizable classes. The network achieved an accuracy of 92.41% on the MNIST dataset for digits “0” to “7” and was conceptually validated through full-wave simulations. Furthermore, to leverage the advantages of this architecture, a 16-class classification task was constructed on the EMNIST dataset. The simulation results confirmed the effectiveness and scalability of the proposed architecture in multi-class recognition scenarios. This strategy exhibits strong application potential in scenarios involving a large number of categories and limited output-plane resources, providing an effective solution for such challenges.
More Accepted manuscripts
Trending on Altmetric
The following article is
Open access
Interpolation-based data augmentation for film thickness regression in atmospheric pressure plasma jet deposition via optical emission spectroscopy
Jia-He Tee
et al
2026
J. Phys. D: Appl. Phys.
59
165205
View article
, Interpolation-based data augmentation for film thickness regression in atmospheric pressure plasma jet deposition via optical emission spectroscopy
PDF
, Interpolation-based data augmentation for film thickness regression in atmospheric pressure plasma jet deposition via optical emission spectroscopy
Advancements in artificial intelligence have facilitated the widespread application of machine learning techniques in industrial, manufacturing, and scientific domains. However, the scarcity of labeled data continues to pose a major challenge for effective analysis and modeling. To address this limitation, we propose an interpolation-based data augmentation method that generates pseudo-labeled data points between sparsely labeled sequences. Time-series spectral data acquired during atmospheric pressure plasma jet thin film deposition are used to interpolate labels for intermediate data points based on feature similarity and temporal order, thereby generating additional training data with estimated labels. We evaluated data augmentation across multiple cycles on three representative regression models, i.e. Lasso, multilayer perceptron (MLP), and extreme gradient boosting, and found that the implementation of data augmentation effectively reduced the mean absolute error (MAE) and mean absolute percentage error (MAPE) in film thickness prediction. In particular, with four augmentation cycles, the MLP achieved the greatest improvement, reducing MAE by 5.5% and MAPE by 16.5% compared with the baseline without augmentation. In addition to improving prediction accuracy, we further examined model robustness, which is quantitatively defined as the relative percentage change in prediction error when outliers are introduced. Under this definition, the proposed augmentation method enhances robustness by mitigating the adverse effects of outlier datasets. These findings demonstrate the effectiveness of the method for regression on sequential process data, particularly under conditions of limited labeled data and the presence of outliers.
The following article is
Open access
Investigation into material effect on cathode spot evolution based on molecular dynamics simulation
Haonan Yang
et al
2026
J. Phys. D: Appl. Phys.
59
165201
View article
, Investigation into material effect on cathode spot evolution based on molecular dynamics simulation
PDF
, Investigation into material effect on cathode spot evolution based on molecular dynamics simulation
The properties of contact materials largely determine the performance of vacuum circuit breakers (VCBs). Consequently, improving material properties through modifications of conventional Cu–Cr alloys has become a central research focus, particularly in the development of VCBs for higher voltage levels. To elucidate the mechanisms underlying material effects on VCB performance, it is essential to investigate cathode spot behaviour, which fundamentally reflects the interaction between contact materials and the vacuum arc. Although numerous simulation studies have been carried out on cathode spot mechanisms, most are restricted to pure Cu contacts. In this study, molecular dynamics simulations are employed to investigate cathode spot evolution in three types of Cu–Cr contacts, categorised according to the relationship between grain size and spot size. To focus specifically on material effects, a simplified two-dimensional thermal model is adopted, and analysis is concentrated on crater profiles. The simulations reveal that Cr spots generally produce more favourable crater profiles than Cu spots. While finer Cu–Cr alloys and nanocrystalline Cu–Cr alloys typically exhibit worse erosion resistance than pure Cr contacts, they can yield improved crater profiles under certain conditions. Based on these results, guidance for material modification of Cu–Cr contacts is proposed. From the perspective of minimising contact erosion and maintaining surface smoothness, cathode spot initiation in the Cu phase should be avoided. Moreover, nanocrystalline Cu–Cr contacts do not necessarily provide significant performance advantages. Finally, comparisons with existing experimental and simulation studies confirm the consistency and validity of the present findings.
The following article is
Open access
Optimization of three-dimensional laminated electrodes for enhanced electroadhesive force
Zichao Chen
et al
2026
J. Phys. D: Appl. Phys.
59
165101
View article
, Optimization of three-dimensional laminated electrodes for enhanced electroadhesive force
PDF
, Optimization of three-dimensional laminated electrodes for enhanced electroadhesive force
Electroadhesion (EA), with its advantages of broad interfacial applicability, switchable adhesion, and low power consumption, is regarded as having prospective applications for the end-effectors of on-orbit spacecraft maintenance robots. However, its reliability in space has been constrained by the planar electrode configurations commonly adopted, which suffer from issues such as low EA force and poor stability. To address this, a three-dimensional (3D) laminated electrode configuration of EA is proposed in this paper. The mechanism for enhancing the EA force in this electrode configuration is revealed through modeling and simulation, leading to the optimization design of its key parameters. An EA force test platform is constructed to systematically compare the EA performances of conventional planar electrodes and the proposed 3D laminated electrodes on different material surfaces (insulator, semiconductor, and conductor). The experimental results demonstrate that the 3D layered electrode configuration exhibits significantly superior EA force compared to planar electrodes, along with enhanced stability. This study provides novel insights and an experimental basis for high-performance EA end-effectors of on-orbit spacecraft maintenance robots.
The following article is
Open access
Thermal transfer characteristics of a phase change composite heat sink based on π-shaped graphene foam with high thermal conductivity and rapid response
Xinbo Zhao
et al
2026
J. Phys. D: Appl. Phys.
View article
, Thermal transfer characteristics of a phase change composite heat sink based on π-shaped graphene foam with high thermal conductivity and rapid response
PDF
, Thermal transfer characteristics of a phase change composite heat sink based on π-shaped graphene foam with high thermal conductivity and rapid response
Solid-liquid transition is characterized by high thermal storage density and nearisothermal endothermic/exothermic processes. Consequently, phase change heat sinks (PCHSs) based on phase change materials (PCMs) hold significant potential for application in heat management of electronic devices under specialized operating conditions. However, existing research still confronts key challenges, including insufficient in-plane thermal conductivity, slow thermal response rates, and inadequate investigation into the effects of encapsulation materials. In this study, a n-octacosane/π-shaped graphene foam (n-octacosane/π-GF) phase change composite (PCC) heat sink is proposed. This design enables rapid in-plane heat spreading while facilitating efficient heat transfer and storage along the thickness direction, thereby synergistically optimizing heat spreading, transfer, and storage performance.Comparative analyses were conducted to evaluate the heat transfer characteristics in both inplane and thickness directions and the thermal management performance of different PCHSs.The integration of aluminum-graphite composite and π-GF was found to enhance the in-plane heat spreading capability and through-thickness heat transfer performance of the PCHS, mitigate in-plane heat accumulation, accelerate the melting of n-octacosane along the thickness direction, and reduce the heat storage duration of n-octacosane. With increasing heat flux density, the safe operating time initially decreases sharply before entering a phase of gradual decline. Relative to pure n-octacosane, the n-octacosane/π-GF composite exhibits a 13-fold enhancement in the through-thickness thermal conductivity and a 110-fold improvement in the in-plane thermal conductivity, with the latter reaching 18.8 W/(m•K).Furthermore, the thermal management performance of the n-octacosane/π-GF PCC encapsulated with aluminum-graphite composite is 2.9 times higher than that of the aluminum alloy encapsulated pure n-octacosane PCHS. This work offers meaningful insights for the design of PCHSs with rapid response and high in-plane thermal conductivity, as well as for the rational selection of encapsulation materials.
The following article is
Open access
State-to-state kinetics and coupled electron–Boltzmann modeling of pulsed RF molecular plasmas
Sagar Pokharel
et al
2026
J. Phys. D: Appl. Phys.
View article
, State-to-state kinetics and coupled electron–Boltzmann modeling of pulsed RF molecular plasmas
PDF
, State-to-state kinetics and coupled electron–Boltzmann modeling of pulsed RF molecular plasmas
Understanding and controlling molecular radio-frequency (RF) plasma characteristics is essential for low-temperature plasma applications, including air-breathing propulsion, plasma-assisted energy systems, and materials processing. Pulsed operation is often preferred for enhanced control but involves inherently transient, multi-scale processes that require robust and coupled modeling approaches. This study develops a closely coupled unsteady electron-Boltzmann and plasma-kinetics framework to investigate the strongly non-equilibrium behavior of pulsed RF molecular plasmas. The framework consistently couples electron, vibrational, and chemical processes, incorporating additional electron loss mechanisms from flow and wall interactions. A detailed state-to-state model for hydrogen (H
), resolving 15 vibrational levels, is implemented to construct a comprehensive plasma kinetics database. Results highlight the limitations of conventional steady-state solvers in capturing transient phenomena. Analysis of the electron energy distribution function (EEDF) under pulsed operation revealed strong non-Maxwellian features during both the pulse-on and pulse-off phases. Furthermore, phase-resolved power absorption demonstrated electron momentum-induced negative power absorption within the RF cycle, indicating complex heating dynamics. The H
vibrational distribution exhibited a highly non-Maxwellian profile that, while appearing two-temperature-like, does not conform to a simple two-temperature model due to the gradual population transition between the two energy regions and the stronger depletion of the H
(v = 14). Quantification of electron power losses indicated that in steady pulsed operation, ionization from vibrationally excited H
(v ≥ 1) and atomic H contributed as significantly to electron production as non-dissociative ionization from ground-state . Additionally, the power gain from super-elastic collisions was significant during the afterglow phase.
The following article is
Open access
Chemical reaction network and kinetic analysis for natural origin gases, C
N, and their mixtures
Hanut Vemulapalli
et al
2026
J. Phys. D: Appl. Phys.
View article
, Chemical reaction network and kinetic analysis for natural origin gases, C4F7N, and their mixtures
PDF
, Chemical reaction network and kinetic analysis for natural origin gases, C4F7N, and their mixtures
For more than half a century SF6 has been the predominant gas insulation medium. Due to its high global warming potential, it is now being replaced with mixtures of natural origin gases (NOG), namely N2, O2 and CO2, either alone or in combination with the strongly electron attaching gas C4F7N. Information about the thermodynamic properties and reaction rates of these mixtures and their decomposition products is essential for predicting their electrical insulation performance. However, currently available reaction rate data is lacking. In this work, we employ an automated chemical network exploration tool to derive an internally consistent reaction mechanism for these mixtures. The mechanism captures the kinetically significant reactions between neutral species and includes the reaction rates for the decomposition of C4F7N, its reactions with its decomposition products, and their reactions with NOG. Our reaction mechanism contains all fluorinated by-products experimentally observed after arcing tests and reveals that the barrier-free decomposition rates of C 4 F 7 N reported in the literature appear to be significantly overestimated based on comparison with available experimental decomposition temperatures. We carry out chemical kinetics calculations to investigate the decomposition by-products of two different C4F7N, CO2, O 2 mixtures under different conditions and show that the presence of C4F7N promotes CO generation, whereas higher O2 concentrations suppress it. We report the volumetric heat capacity (ρCp ) based on chemical kinetics rather than chemical equilibrium, as done in existing literature, and show that the peaks in ρC p that are associated with high thermal interruption performance shift to lower temperatures when the gas is cooled. The full reaction mechanism file is provided to support and enable further studies. In the future, we aim to use this reaction mechanism to model the stepped leader dielectric breakdown process in these mixtures.
The following article is
Open access
Photonic interactions with semiconducting barrier discharges
Ayah Soundous Taihi and David Z Pai 2026
J. Phys. D: Appl. Phys.
59
135203
View article
, Photonic interactions with semiconducting barrier discharges
PDF
, Photonic interactions with semiconducting barrier discharges
Semiconducting Barrier Discharges (SeBDs) generate uniform ionization waves in air at atmospheric pressure. In this work, we investigate how externally applied irradiation synchronized with the discharge can mimic photoconductive-type coupling between the plasma and the semiconductor surface. By illuminating the Si–SiO
interface with nanosecond pulsed irradiation at wavelengths from 532 nm to 1064 nm, and using fast imaging, optical emission spectroscopy, and current–voltage measurements, we show evidence that the photoexcitation of charge carriers in silicon enhances the plasma emission and increases the inferred reduced electric field, with no significant change in the electrical energy. The magnitude and thresholds of these responses depend on wavelength. By comparing the SeBD to a metal-oxide-semiconductor photodetector, this behavior can be explained by the absorption length. This length determines whether carriers are photogenerated inside the depletion region at the SiO
–Si interface where they are efficiently separated and undergo impact ionization amplification, or deeper in the silicon bulk where carrier separation is weaker and free-carrier absorption diminishes the quantum efficiency. These results focus on the microscopic processes governing the plasma-semiconductor coupling and highlight how the optoelectronic properties of silicon can influence surface ionization waves.
The following article is
Open access
The 2025 thermionic converters roadmap
Alessandro Bellucci
et al
2026
J. Phys. D: Appl. Phys.
View article
, The 2025 thermionic converters roadmap
PDF
, The 2025 thermionic converters roadmap
Thermionic technologies are based on electron emission from a material occurring at high temperatures, following the physical mechanism discovered by Richardson at the beginning of the 20th century. Although thermionic emitters were successfully used to develop commercial electronic devices, sensors, and electron sources, the large potential of this technology for the development of energetically active devices for space and terrestrial applications is still unexploited, since several challenges remain unresolved to enable practical implementation of competitive energy converters. This Roadmap aims to collect the main efforts of the research and industrial community focused on thermionic technologies, covering aspects related to the active materials, components and system engineering for the development of related devices. Additionally, contributions related to the development of promising approaches for the prediction and design of the systems, as well as hybridization with other technologies or physical mechanisms, are also considered. The scope is to provide a guide for researchers and developers who are experienced on this topic - but also who are starting to work with it - by analytically describing state-of-the-art, technological challenges and future paths for a full development of thermionic technologies.
The following article is
Open access
Chemical bonding evolution of near-surface nitrogen and defects in ultra-low-energy nitrogen implanted (100) single crystal diamond probed by synchrotron X-ray spectroscopies
Amaresh Das
et al
2026
J. Phys. D: Appl. Phys.
View article
, Chemical bonding evolution of near-surface nitrogen and defects in ultra-low-energy nitrogen implanted (100) single crystal diamond probed by synchrotron X-ray spectroscopies
PDF
, Chemical bonding evolution of near-surface nitrogen and defects in ultra-low-energy nitrogen implanted (100) single crystal diamond probed by synchrotron X-ray spectroscopies
Controlled modification of diamond surfaces is essential for achieving stable, high coherence shallow negatively charged nitrogen–vacancy (NV⁻) centers for quantum technologies. Here, hydrogen-terminated (100) single crystal diamond surfaces were modified by ultra-low-energy (100 eV) N2+ implantation, corresponding to an effective nitrogen energy of 50 eV per atom. The implantation-induced bonding configurations and their thermal evolution were investigated using synchrotron-based, energy-dependent X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. XPS reveals the formation of C–N and C=N bonding states together with implantation induced surface carbon defects associated with sp2-like carbon, structural disorder, and stress. NEXAFS identifies distinct unoccupied σ* and π* surface states while preserving the characteristic excitonic and second bandgap features of diamond, with no evidence of long-range graphitic domains in near-surface region. In situ annealing at 700 °C leads to preferential nitrogen desorption from C=N sites, stabilization of thermally robust C–N bonding, recovery of sp3 carbon order through defect annihilation and nitrogen substitution, and relaxation of implantation induced stress, leaving a small stable fraction of near-surface sp2 carbon. A mechanistic energy level analysis indicates that π*(C=N) and σ*(C–N) states lie above the NV⁻ ground state and are less detrimental to shallow NV⁻ charge stability, whereas sp2 carbon π* states located approximately 1.85 eV below the NV⁻ ground state may act as charge traps. These findings highlight the importance of minimizing surface sp2 carbon. Overall, this study elucidates the bonding and electronic structure of ultra-low-energy nitrogen-modified diamond surfaces and provides guidance for engineering diamond terminations through N2+ implantation for stabilization of shallow NV⁻ centers.
The following article is
Open access
Acoustic excitations and coherent oscillations in macroscopic solid-state structures
Franco Braga
et al
2026
J. Phys. D: Appl. Phys.
View article
, Acoustic excitations and coherent oscillations in macroscopic solid-state structures
PDF
, Acoustic excitations and coherent oscillations in macroscopic solid-state structures
The propagation of acoustic waves in steel tendons is investigated within the framework of a research for non invasive localisation of defects in metal structures embedded in concrete. The possibility of determining the status and quality of the structures and eventually localising defects within them is demonstrated both in the frequency and time domain by using piezoelectric sensors activated by tiny mechanical excitations. A very interesting phenomenon is observed when defects are located at "nodal" points of one-dimensional bars/wires. In this case, the oscillations induced by the light mechanical excitations give rise to piezos output voltages whose spectral components amplitude exceeds up to six orders of magnitude the background noise level. This phenomenon is consistently observed when one, two, or three "nodal" defects are present in the bars and is generated by coherent oscillations of the sections of the bars separated by the defects. Finally, an application of 2 our technique to the post-tensioned structure of a highway viaduct is presented, confirming its potential for non-destructive testing and structural health monitoring.
More Open Access articles
Four peak and high angle tilted insensitive surface plasmon resonance graphene absorber based on circular etching square window
Zhou Ai
et al
2025
J. Phys. D: Appl. Phys.
58
185305
View article
, Four peak and high angle tilted insensitive surface plasmon resonance graphene absorber based on circular etching square window
PDF
, Four peak and high angle tilted insensitive surface plasmon resonance graphene absorber based on circular etching square window
This article introduces a new type of graphene-based perfect absorber that features tunability across four wave peaks and high sensitivity, consisting of Ag–SiO
–graphene. By controlling the Fermi level and relaxation time of graphene, the tunability of the absorber is achieved, and by changing the refractive index of SiO
, the selectivity of the resonant wavelength is realized. The results show that the absorber has an average absorption rate of 98.54% at four wavelengths: 2092.24 nm, 2180.67 nm, 2230.08 nm, and 2336.17 nm. The electric field distribution intensity is simulated to verify whether it meets the impedance matching theory, exploring the physical mechanism behind the high absorption rates at these four peaks. Different polarizations and inclined incidence angles are investigated to explore the absorber’s insensitivity to polarization, demonstrating excellent insensitivity within an inclination angle range from 0° to 65°. The sensitivities of the four peaks are 501.54 nm RIU
−1
, 565.76 nm RIU
−1
, 605.47 nm RIU
−1
, and 582.70 nm RIU
−1
, respectively. Finally, the practical application of the absorber in detecting aqueous solutions of 10%, 20%, 25% glucose solutions, and 30%, 50% sugar solutions is simulated, and the results show that the absorber has good sensing performance. This paper’s absorber features four-peak perfect absorption and excellent tilt insensitivity, good refractive index sensitivity, and holds great potential applications in detectors and optical communication systems.
The following article is
Open access
The 2018 GaN power electronics roadmap
H Amano
et al
2018
J. Phys. D: Appl. Phys.
51
163001
View article
, The 2018 GaN power electronics roadmap
PDF
, The 2018 GaN power electronics roadmap
Gallium nitride (GaN) is a compound semiconductor that has tremendous potential to facilitate economic growth in a semiconductor industry that is silicon-based and currently faced with diminishing returns of performance versus cost of investment. At a material level, its high electric field strength and electron mobility have already shown tremendous potential for high frequency communications and photonic applications. Advances in growth on commercially viable large area substrates are now at the point where power conversion applications of GaN are at the cusp of commercialisation. The future for building on the work described here in ways driven by specific challenges emerging from entirely new markets and applications is very exciting. This collection of GaN technology developments is therefore not itself a road map but a valuable collection of global state-of-the-art GaN research that will inform the next phase of the technology as market driven requirements evolve. First generation production devices are igniting large new markets and applications that can only be achieved using the advantages of higher speed, low specific resistivity and low saturation switching transistors. Major investments are being made by industrial companies in a wide variety of markets exploring the use of the technology in new circuit topologies, packaging solutions and system architectures that are required to achieve and optimise the system advantages offered by GaN transistors. It is this momentum that will drive priorities for the next stages of device research gathered here.
The following article is
Open access
The 2022 Plasma Roadmap: low temperature plasma science and technology
I Adamovich
et al
2022
J. Phys. D: Appl. Phys.
55
373001
View article
, The 2022 Plasma Roadmap: low temperature plasma science and technology
PDF
, The 2022 Plasma Roadmap: low temperature plasma science and technology
The 2022 Roadmap is the next update in the series of Plasma Roadmaps published by
Journal of Physics
D with the intent to identify important outstanding challenges in the field of low-temperature plasma (LTP) physics and technology. The format of the Roadmap is the same as the previous Roadmaps representing the visions of 41 leading experts representing 21 countries and five continents in the various sub-fields of LTP science and technology. In recognition of the evolution in the field, several new topics have been introduced or given more prominence. These new topics and emphasis highlight increased interests in plasma-enabled additive manufacturing, soft materials, electrification of chemical conversions, plasma propulsion, extreme plasma regimes, plasmas in hypersonics, data-driven plasma science and technology and the contribution of LTP to combat COVID-19. In the last few decades, LTP science and technology has made a tremendously positive impact on our society. It is our hope that this roadmap will help continue this excellent track record over the next 5–10 years.
Applications of magnetic nanoparticles in biomedicine
Q A Pankhurst
et al
2003
J. Phys. D: Appl. Phys.
36
R167
View article
, Applications of magnetic nanoparticles in biomedicine
PDF
, Applications of magnetic nanoparticles in biomedicine
The physical principles underlying some current biomedical applications of magnetic nanoparticles are reviewed. Starting from well-known basic concepts, and drawing on examples from biology and biomedicine, the relevant physics of magnetic materials and their responses to applied magnetic fields are surveyed. The way these properties are controlled and used is illustrated with reference to (i) magnetic separation of labelled cells and other biological entities; (ii) therapeutic drug, gene and radionuclide delivery; (iii) radio frequency methods for the catabolism of tumours via hyperthermia; and (iv) contrast enhancement agents for magnetic resonance imaging applications. Future prospects are also discussed.
Plasma-activated water: generation, origin of reactive species and biological applications
Renwu Zhou
et al
2020
J. Phys. D: Appl. Phys.
53
303001
View article
, Plasma-activated water: generation, origin of reactive species and biological applications
PDF
, Plasma-activated water: generation, origin of reactive species and biological applications
Novel plasma-based technologies that offer maximum efficiency at minimal environmental costs are expected to further promote the sustainable societal and economic development. Unique transfer of chemical reactivity and energy from gaseous plasmas to water takes place in the absence of any other chemicals, but results in a product with a notable transient broad-spectrum biological activity, referred to as plasma-activated water (PAW). These features make PAW a green prospective solution for a wide range of biotechnology applications, from water purification to biomedicine. Here, we present a succinct review of how novel, efficient methods based on non-equilibrium reactive plasma chemistries can be applied to low-cost natural water sources to produce a prospective product with a wide range of applications while at the same time minimising the process steps and dramatically reducing the use of expensive and/or hazardous reagents. Despite the recent exciting developments in this field, there presently is no topical review which specifically focuses on the underlying physics and chemistry related to plasma-activated water. We focus specifically on the PAW generation, origin of reactive species present in PAW, its related analytical chemistry and potentially different mechanisms that regulate the bio-activities of PAW in different biotech-applications and their roles in determining PAW efficacy and selectivity. We then review recent advances in our understanding of plasma-water interactions, briefly outlining current and proposed applications of PAW in agriculture, food and biomedicine. Finally, we outline future research directions and challenges that may hinder translation of these technologies into real-life applications. Overall, this review will provide much needed insights into the fundamental aspects of PAW chemistry required for optimization of the biochemical activity of PAW and translation of this environment- and human-health-friendly, and energy-efficient strategy into real life applications.
Hydrostatic limits of 11 pressure transmitting media
S Klotz
et al
2009
J. Phys. D: Appl. Phys.
42
075413
View article
, Hydrostatic limits of 11 pressure transmitting media
PDF
, Hydrostatic limits of 11 pressure transmitting media
We present a systematic and comparative study of the pressure-induced solidification of 11 frequently used pressure transmitting fluids using the ruby fluorescence technique in a diamond anvil cell. These fluids are 1 : 1 and 5 : 1 iso-n pentane, 4 : 1 deuterated methanol–ethanol, 16 : 3 : 1 deuterated methanol–ethanol-water, 1 : 1 FC84-FC87 Fluorinert, Daphne 7474, silicone oil, as well as nitrogen, neon, argon and helium. The data provide practical guidelines for the use of these fluids in high pressure experiments up to 50 GPa.
Revival of the magnetoelectric effect
Manfred Fiebig 2005
J. Phys. D: Appl. Phys.
38
R123
View article
, Revival of the magnetoelectric effect
PDF
, Revival of the magnetoelectric effect
Recent research activities on the linear magnetoelectric (ME) effect—induction of magnetization by an electric field or of polarization by a magnetic field—are reviewed. Beginning with a brief summary of the history of the ME effect since its prediction in 1894, the paper focuses on the present revival of the effect. Two major sources for ‘large’ ME effects are identified. (i) In composite materials the ME effect is generated as a product property of a magnetostrictive and a piezoelectric compound. A linear ME polarization is induced by a weak ac magnetic field oscillating in the presence of a strong dc bias field. The ME effect is large if the ME coefficient coupling the magnetic and electric fields is large. Experiments on sintered granular composites and on laminated layers of the constituents as well as theories on the interaction between the constituents are described. In the vicinity of electromechanical resonances a ME voltage coefficient of up to 90 V cm
−1
Oe
−1
is achieved, which exceeds the ME response of single-phase compounds by 3–5 orders of magnitude. Microwave devices, sensors, transducers and heterogeneous read/write devices are among the suggested technical implementations of the composite ME effect. (ii) In multiferroics the internal magnetic and/or electric fields are enhanced by the presence of multiple long-range ordering. The ME effect is strong enough to trigger magnetic or electrical phase transitions. ME effects in multiferroics are thus ‘large’ if the corresponding contribution to the free energy is large. Clamped ME switching of electrical and magnetic domains, ferroelectric reorientation induced by applied magnetic fields and induction of ferromagnetic ordering in applied electric fields were observed. Mechanisms favouring multiferroicity are summarized, and multiferroics in reduced dimensions are discussed. In addition to composites and multiferroics, novel and exotic manifestations of ME behaviour are investigated. This includes (i) optical second harmonic generation as a tool to study magnetic, electrical and ME properties in one setup and with access to domain structures; (ii) ME effects in colossal magnetoresistive manganites, superconductors and phosphates of the Li
PO
type; (iii) the concept of the toroidal moment as manifestation of a ME dipole moment; (iv) pronounced ME effects in photonic crystals with a possibility of electromagnetic unidirectionality. The review concludes with a summary and an outlook to the future development of magnetoelectrics research.
The following article is
Open access
The 2023 terahertz science and technology roadmap
Alfred Leitenstorfer
et al
2023
J. Phys. D: Appl. Phys.
56
223001
View article
, The 2023 terahertz science and technology roadmap
PDF
, The 2023 terahertz science and technology roadmap
Terahertz (THz) radiation encompasses a wide spectral range within the electromagnetic spectrum that extends from microwaves to the far infrared (100 GHz–∼30 THz). Within its frequency boundaries exist a broad variety of scientific disciplines that have presented, and continue to present, technical challenges to researchers. During the past 50 years, for instance, the demands of the scientific community have substantially evolved and with a need for advanced instrumentation to support radio astronomy, Earth observation, weather forecasting, security imaging, telecommunications, non-destructive device testing and much more. Furthermore, applications have required an emergence of technology from the laboratory environment to production-scale supply and in-the-field deployments ranging from harsh ground-based locations to deep space. In addressing these requirements, the research and development community has advanced related technology and bridged the transition between electronics and photonics that high frequency operation demands. The multidisciplinary nature of THz work was our stimulus for creating the 2017 THz Science and Technology Roadmap (Dhillon
et al
2017
J. Phys. D: Appl. Phys.
50
043001). As one might envisage, though, there remains much to explore both scientifically and technically and the field has continued to develop and expand rapidly. It is timely, therefore, to revise our previous roadmap and in this 2023 version we both provide an update on key developments in established technical areas that have important scientific and public benefit, and highlight new and emerging areas that show particular promise. The developments that we describe thus span from fundamental scientific research, such as THz astronomy and the emergent area of THz quantum optics, to highly applied and commercially and societally impactful subjects that include 6G THz communications, medical imaging, and climate monitoring and prediction. Our Roadmap vision draws upon the expertise and perspective of multiple international specialists that together provide an overview of past developments and the likely challenges facing the field of THz science and technology in future decades. The document is written in a form that is accessible to policy makers who wish to gain an overview of the current state of the THz art, and for the non-specialist and curious who wish to understand available technology and challenges. A such, our experts deliver a ‘snapshot’ introduction to the current status of the field and provide suggestions for exciting future technical development directions. Ultimately, we intend the Roadmap to portray the advantages and benefits of the THz domain and to stimulate further exploration of the field in support of scientific research and commercial realisation.
YIG magnonics
A A Serga
et al
2010
J. Phys. D: Appl. Phys.
43
264002
View article
, YIG magnonics
PDF
, YIG magnonics
Early experiments in magnonics were made using ferrite samples, largely due to the intrinsically low magnetic (spin-wave) damping in these materials. Historically, magnonic phenomena were studied on micrometre to millimetre length scales. Today, the principal challenge in applied magnonics is to create sub-micrometre devices using modern polycrystalline magnetic alloys. However, until certain technical obstacles are overcome in these materials, ferrites—in particular yttrium iron garnet (YIG)—remain a valuable source of insight. At a time when interest in magnonic systems is particularly strong, it is both useful and timely to review the main scientific results of YIG magnonics of the last two decades, and to discuss the transferability of the concepts and ideas learned in ferrite materials to modern nano-scale systems.
A review of ceramic, polymer and composite piezoelectric materials
Mahpara Habib
et al
2022
J. Phys. D: Appl. Phys.
55
423002
View article
, A review of ceramic, polymer and composite piezoelectric materials
PDF
, A review of ceramic, polymer and composite piezoelectric materials
Piezoelectric materials have been studied for nearly a century now. Initially employed in sonar technology, piezoelectric materials now have a vast set of applications including energy harvesting, sensing and actuation, and have found their way into our everyday lives. Piezoelectric material properties are being further enhanced to improve their performance and be used in novel applications. This review provides an overview of piezoelectric materials and offers a material science and fabrication perspective on progress towards the development of practical piezoelectric energy harvesters and sensors. Piezoelectric materials have been divided into the three following classes for this review: ceramics, polymers and composites. The prominent materials under each class are examined and compared, with a focus on their linear piezoelectric response in the d
33
mode. The three classes of piezoelectric materials are also compared qualitatively for a range of metrics, and the applications that each material class are best suited for is discussed. Novel piezoelectric materials such as ferroelectrets and nanogenerator devices are also reviewed here. It is shown that ceramic piezoelectric materials have strong piezoelectric properties but are stiff and brittle, whereas polymer piezoelectric materials are flexible and lightweight but do not exhibit very good piezoelectric performance. Composite materials are concluded to possess the advantages of both ceramic and polymer materials, with room to tailor-fit properties by modifying the structure and composition.
Journal links
Submit an article
About the journal
Editorial Board
Author guidelines
Review for this journal
Publication charges
Awards
Journal collections
Pricing and ordering
Journal information
1968-present
Journal of Physics D: Applied Physics
doi: 10.1088/issn.0022-3727
Online ISSN: 1361-6463
Print ISSN: 0022-3727
Journal history
1968-present
Journal of Physics D: Applied Physics
1950-1967
British Journal of Applied Physics