Semiconductor Science and Technology - IOPscience

Semiconductor Science and Technology - IOPscience
Semiconductor Science and Technology
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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.
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Semiconductor Science and Technology
is IOP's journal dedicated to semiconductor research. The journal publishes cutting-edge research on the physical properties of semiconductors and their applications.
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The following article is
Open access
Recent advances in GaN-based power devices and integration
Yixin Xiong
et al
2025
Semicond. Sci. Technol.
40
033002
View article
, Recent advances in GaN-based power devices and integration
PDF
, Recent advances in GaN-based power devices and integration
Gallium nitride (GaN) has gained traction in replacing silicon for power electronics applications, due to its high breakdown field, high mobility 2D electron gas, and effective n/p-type doping. This paper reviews three important topics of GaN power devices. One is the voltage-blocking structures needed to operate at high voltage while minimizing conduction loss and switching loss. Another one is the structure used to achieve normally-off operation, which is often required for power electronics. The third topic is the monolithic integration of gate drivers and power switches to achieve the ultimate switching speed at a low cost.
The following article is
Open access
An introduction to InP-based generic integration technology
Meint Smit
et al
2014
Semicond. Sci. Technol.
29
083001
View article
, An introduction to InP-based generic integration technology
PDF
, An introduction to InP-based generic integration technology
Photonic integrated circuits (PICs) are considered as the way to make photonic systems or subsystems cheap and ubiquitous. PICs still are several orders of magnitude more expensive than their microelectronic counterparts, which has restricted their application to a few niche markets. Recently, a novel approach in photonic integration is emerging which will reduce the R&D and prototyping costs and the throughput time of PICs by more than an order of magnitude. It will bring the application of PICs that integrate complex and advanced photonic functionality on a single chip within reach for a large number of small and larger companies and initiate a breakthrough in the application of Photonic ICs. The paper explains the concept of generic photonic integration technology using the technology developed by the COBRA research institute of TU Eindhoven as an example, and it describes the current status and prospects of generic InP-based integration technology.
The following article is
Open access
Resistive switching memories based on metal oxides: mechanisms, reliability and scaling
Daniele Ielmini 2016
Semicond. Sci. Technol.
31
063002
View article
, Resistive switching memories based on metal oxides: mechanisms, reliability and scaling
PDF
, Resistive switching memories based on metal oxides: mechanisms, reliability and scaling
With the explosive growth of digital data in the era of the Internet of Things (IoT), fast and scalable memory technologies are being researched for data storage and data-driven computation. Among the emerging memories, resistive switching memory (RRAM) raises strong interest due to its high speed, high density as a result of its simple two-terminal structure, and low cost of fabrication. The scaling projection of RRAM, however, requires a detailed understanding of switching mechanisms and there are potential reliability concerns regarding small device sizes. This work provides an overview of the current understanding of bipolar-switching RRAM operation, reliability and scaling. After reviewing the phenomenological and microscopic descriptions of the switching processes, the stability of the low- and high-resistance states will be discussed in terms of conductance fluctuations and evolution in 1D filaments containing only a few atoms. The scaling potential of RRAM will finally be addressed by reviewing the recent breakthroughs in multilevel operation and 3D architecture, making RRAM a strong competitor among future high-density memory solutions.
The following article is
Open access
Dawn of nitride ferroelectric semiconductors: from materials to devices
Ping Wang
et al
2023
Semicond. Sci. Technol.
38
043002
View article
, Dawn of nitride ferroelectric semiconductors: from materials to devices
PDF
, Dawn of nitride ferroelectric semiconductors: from materials to devices
III-nitride semiconductors are promising optoelectronic and electronic materials and have been extensively investigated in the past decades. New functionalities, such as ferroelectricity, ferromagnetism, and superconductivity, have been implanted into III-nitrides to expand their capability in next-generation semiconductor and quantum technologies. The recent experimental demonstration of ferroelectricity in nitride materials, including ScAl(Ga)N, boron-substituted AlN, and hexagonal BN, has inspired tremendous research interest. Due to the large remnant polarization, high breakdown field, high Curie temperature, and significantly enhanced piezoelectric, linear and nonlinear optical properties, nitride ferroelectric semiconductors have enabled a wealth of applications in electronic, ferroelectronic, acoustoelectronic, optoelectronic, and quantum devices and systems. In this review, the development of nitride ferroelectric semiconductors from materials to devices is discussed. While expounding on the unique advantages and outstanding achievements of nitride ferroelectrics, the existing challenges and promising prospects have been also discussed.
The following article is
Open access
Flexible diodes for radio frequency (RF) electronics: a materials perspective
James Semple
et al
2017
Semicond. Sci. Technol.
32
123002
View article
, Flexible diodes for radio frequency (RF) electronics: a materials perspective
PDF
, Flexible diodes for radio frequency (RF) electronics: a materials perspective
Over the last decade, there has been increasing interest in transferring the research advances in radiofrequency (RF) rectifiers, the quintessential element of the chip in the RF identification (RFID) tags, obtained on rigid substrates onto plastic (flexible) substrates. The growing demand for flexible RFID tags, wireless communications applications and wireless energy harvesting systems that can be produced at a low-cost is a key driver for this technology push. In this topical review, we summarise recent progress and status of flexible RF diodes and rectifying circuits, with specific focus on materials and device processing aspects. To this end, different families of materials (e.g. flexible silicon, metal oxides, organic and carbon nanomaterials), manufacturing processes (e.g. vacuum and solution processing) and device architectures (diodes and transistors) are compared. Although emphasis is placed on performance, functionality, mechanical flexibility and operating stability, the various bottlenecks associated with each technology are also addressed. Finally, we present our outlook on the commercialisation potential and on the positioning of each material class in the RF electronics landscape based on the findings summarised herein. It is beyond doubt that the field of flexible high and ultra-high frequency rectifiers and electronics as a whole will continue to be an active area of research over the coming years.
The following article is
Open access
Low resistance distributed polarization doped p-AlGaN layer for 265 nm LEDs operating at very high current densities
M Grigoletto
et al
2026
Semicond. Sci. Technol.
41
025019
View article
, Low resistance distributed polarization doped p-AlGaN layer for 265 nm LEDs operating at very high current densities
PDF
, Low resistance distributed polarization doped p-AlGaN layer for 265 nm LEDs operating at very high current densities
Ultraviolet-C light-emitting diodes (UVC-LEDs) with low resistance distributed polarization doped (DPD) p-type AlGaN layers are investigated. The UV-transparent DPD p-AlGaN layers provide high hole carrier densities in high aluminum mole fraction UVC-LEDs emitting near 265 nm. The influence of the DPD p-AlGaN layer thickness (50–320 nm) on the electrical and optical characteristics of UVC-LEDs is systematically evaluated. Despite the large variation of the DPD layer thickness, the voltages at 50 mA of the devices remained largely unchanged, demonstrating that the highly conductive p-type DPD layers do not significantly contribute to the series resistance. Nevertheless, UVC-LEDs with thinner DPD p-AlGaN layers exhibited higher output powers but also increased leakage currents. Capacitance–voltage (C–V) measurements show that the hole concentration increases from 6 × 10
17
cm
−3
to 4 × 10
18
cm
−3
with decreasing p-AlGaN DPD thickness from 320 nm to 50 nm consistent with simulation results. Under pulsed operation, UVC-LEDs were able to operate at very high current densities of up to 90 kA cm
−2
without breaking down. The findings of this study establish DPD p-AlGaN layers as a promising approach for high-performance UVC-LEDs, laser diodes and electronic devices.
The following article is
Open access
The suitability of ultrasonic and megasonic cleaning of nanoscale patterns in ammonia hydroxide solutions for particle removal and feature damage
Chun-Lin Chu
et al
2020
Semicond. Sci. Technol.
35
045001
View article
, The suitability of ultrasonic and megasonic cleaning of nanoscale patterns in ammonia hydroxide solutions for particle removal and feature damage
PDF
, The suitability of ultrasonic and megasonic cleaning of nanoscale patterns in ammonia hydroxide solutions for particle removal and feature damage
In this study, usually, arrays of square or rectangular piezo devices bonded to a substrate and spaced as close together as possible for transduction for efficient megasonic cleaning, megasonic cleaning is applied to removing sidewall particles during post-silicon etch cleaning. A system was developed containing different measures of ultrasonic and megasonic processes, generated by adjusting the power in NH
OH. Megasonic waves in the gap between the wafer and the megasonic transducer ensure uniform sonic energy across the whole wafer. The generation of radicals is promoted by megasonic energy, such that residue removal occurs in dilute solution. The feature damage for the megasonic cleaning decreased in the NH
OH solution compared to ultrasonic. Moreover, the mechanical force of the bubble cavitation generated by megasonic cleaning also improves residue removal and enhances the mass transfer rate. Extreme cavitation is beneficial for removing particles but can damage wafer features. The damage caused by ultrasonic cleaning is significantly larger than megasonic cleaning. Compared with typical methods of silicon oxide residues removal, this megasonic process has a low material loss and a high residue removal efficiency for via, with a high aspect ratio. In addition, it minimizes defects to structures. These results suggest that megasonic cleaning can be applied to the nanoparticle cleaning process. Megasonic cleaning is quickly becoming an efficient method for post process cleaning in IC fabrication processes.
The following article is
Open access
Design of step-graded AlGaN buffers for GaN-on-Si heterostructures grown by MOCVD
Saptarsi Ghosh
et al
2023
Semicond. Sci. Technol.
38
044001
View article
, Design of step-graded AlGaN buffers for GaN-on-Si heterostructures grown by MOCVD
PDF
, Design of step-graded AlGaN buffers for GaN-on-Si heterostructures grown by MOCVD
For the growth of low-defect crack-free GaN heterostructures on large-area silicon substrates, compositional grading of AlGaN is a widely adapted buffer technique to restrict the propagation of lattice-mismatch induced defects and balance the thermal expansion mismatch-induced tensile stress. So far, a consolidation of the design strategy of such step-graded buffers has been impaired by the incomplete understanding of the effect of individual buffer design parameters on the mechanical and microstructural properties of the epilayers. Herein, we have analyzed a series of metal-organic chemical vapor deposition grown GaN/graded-AlGaN/AlN/Si heterostructures through
in situ
curvature measurements and post-growth x-ray diffraction (XRD). Our results reveal that in such epi structures, the GaN layer itself induces more compressive stress than the AlGaN buffer, but the underlying AlGaN layers dictate the magnitude of this stress. Furthermore, for a fixed AlGaN buffer thickness, the mean-stress accumulated during the GaN growth is found to be correlated with its structural properties. Specifically, one
m thick GaN layers that acquire 1.50 GPa or higher compressive mean-stress are seen to possess
XRD
-FWHM values less than 650 arc-sec. Also, the evolution of instantaneous stresses during the growth of the AlGaN layers is found to be a valuable indicator for buffer optimization, and composition difference between successive layers is established as a crucial criterion. The results also show that increasing the total buffer thickness (for a fixed number of steps) or increasing the number of steps (for a fixed total buffer thickness) may not always be beneficial. Irrespective of the buffer thickness, optimized high electron mobility transistor structures show similarly low sheet-resistance (∼350 Ω □)
−1
and high mobility (∼2000 cm
−1
−1
) at room temperature.
The following article is
Open access
Temperature dependent characteristics of AlGaAsSb single photon avalanche diodes
Jonathan Taylor-Mew
et al
2026
Semicond. Sci. Technol.
41
045005
View article
, Temperature dependent characteristics of AlGaAsSb single photon avalanche diodes
PDF
, Temperature dependent characteristics of AlGaAsSb single photon avalanche diodes
Near-infrared single photon avalanche diodes (SPADs) are practical single photon detectors, particularly for applications requiring high operating temperatures. Compared to established InP SPADs, AlGaAsSb SPAD offers superior thermal stability but currently exhibit lower single photon detection efficiency. To improve their performance, origin(s) of AlGaAsSb SPAD’s dark count rate (DCR) and detection efficiency versus overbias characteristics should be investigated. We explore these by performing extensive DCR and SPDE measurements on InGaAs/AlGaAsSb SPADs in gated mode at relevant temperatures (200–290 K). The maximum SPDE at 1550 nm wavelength was 31 (4 V overbias) and 20% (3 V overbias) at 200 and 250 K, respectively, higher than earlier reports of AlGaAsSb SPADs. DCR data analyses show that the tunneling current is a dominant DCR mechanism over the range studied. It most likely originated from the InGaAs absorber, despite an attempt to reduce the electric field in the design. It is therefore necessary to ensure the entire InGaAs absorber does not experience a relatively high electric field in future designs of AlGaAsSb SPADs. If AlGaAsSb SPADs without tunneling current can be achieved, their single photon detection performance is expected to match that of InP SPADs at least, while exhibiting superior thermal stability.
Half-Heusler compounds: novel materials for energy and spintronic applications
F Casper
et al
2012
Semicond. Sci. Technol.
27
063001
View article
, Half-Heusler compounds: novel materials for energy and spintronic applications
PDF
, Half-Heusler compounds: novel materials for energy and spintronic applications
Half-Heusler compounds are an impressive class of materials with a huge potential for different applications such as future energy applications and for spintronics. The semiconducting Heusler compounds can be identified by the number of valence electrons. The band gap can be tuned between 0 and 4 eV by the electronegativity difference of the constituents. Magnetism can be introduced in these compounds by using rare-earth elements, manganese or ‘electron’ doping. Thus, there is a great interest in the fields of thermoelectrics, solar cells and diluted magnetic semiconductors. The combination of different properties such as superconductivity and topological edge states leads to new multifunctional materials, which have the potential to revolutionize technological applications. Here, we review the structure, the origin of the band gap and the functionalities of semiconducting half-Heusler compounds.
The following article is
Open access
Phosphorus vacancy as a dominant donor in n-InP single crystals grown by VGF method
Yihan Bai
et al
2026
Semicond. Sci. Technol.
41
045016
View article
, Phosphorus vacancy as a dominant donor in n-InP single crystals grown by VGF method
PDF
, Phosphorus vacancy as a dominant donor in n-InP single crystals grown by VGF method
S-doped and Fe-doped InP single crystals grown by vertical gradient freezing (VGF) method have been characterized and compared by density, lattice parameter, photoluminescence spectroscopy (PL), Hall effect and glow discharge mass spectroscopy measurements. The density of S-doped InP crystals decreases apparently with increasing carrier concentration, implying the existence of vacancy defects with high concentration. Most of the n-InP single crystals exhibit a much higher carrier concentration than the S doping concentration and a significant compensation from acceptors irrelevant to the impurity. Lattice parameter increases with the increase in carrier concentration of the n-type InP single crystals with practical S doping concentration close to each other. PL results demonstrate a donor defect with energy level above the conduction band bottom. These results are explained by the formation of both phosphorus vacancy and indium vacancy in the VGF growth process, acting as donor and acceptor in the n-InP single crystal, respectively. The presence of phosphorus vacancy defects with high concentration dominates the anomalous density variation in S-doped InP and has a significant impact on its electrical properties. The formation mechanism of vacancy defects is discussed based on the theory of defect thermodynamics and formation energy.
Effect of two-dimensional nonlocal screening on mobility of electrons in transition-metal dichalcogenide monolayers
Aram Manaselyan
et al
2026
Semicond. Sci. Technol.
41
045015
View article
, Effect of two-dimensional nonlocal screening on mobility of electrons in transition-metal dichalcogenide monolayers
PDF
, Effect of two-dimensional nonlocal screening on mobility of electrons in transition-metal dichalcogenide monolayers
A new mechanism governing carrier scattering in monolayer transition-metal dichalcogenides (TMDs) is investigated using the idea of two-dimensional nonlocal dielectric screening introduced by Cudazzo
et al
(2011
Phys. Rev. B
84
085406). Analytical expressions are derived for the transport relaxation time and electron mobility, considering scattering by Coulomb impurities in TMD monolayers placed on different substrates. The analysis demonstrates that inclusion of nonlocal screening significantly enhances electron mobility. Although mobility decreases as temperature rises, the relative increase attributed to nonlocal screening becomes more pronounced, reaching a factor of approximately 6–9 at room temperature for a SiO
substrate.
The following article is
Open access
Dosimetry for proton therapy using a
-Ga
metal–semiconductor–metal detector with low-noise amplification
Hunter D Ellis
et al
2026
Semicond. Sci. Technol.
41
045014
View article
, Dosimetry for proton therapy using a β-Ga2O3 metal–semiconductor–metal detector with low-noise amplification
PDF
, Dosimetry for proton therapy using a β-Ga2O3 metal–semiconductor–metal detector with low-noise amplification
Intensity-modulated proton therapy (IMPT) employs proton radiation rather than conventional x-rays to treat cancerous tumors. This approach offers significant advantages by minimizing the radiation exposure of surrounding healthy tissue, leading to improved patient outcomes and reduced side effects compared to traditional x-ray therapy. To ensure patient safety, each treatment plan must be experimentally validated before clinical implementation. However, current dosimetry devices face limitations in performing angled beam measurements and obtaining multi-depth assessments, both of which are essential for verifying IMPT treatment plans. In this study, the performance of a
-Ga
-based metal–semiconductor–metal detector with a low-noise amplifier has been studied and evaluated under various proton radiation doses and energy levels delivered by a MEVION S250i proton accelerator. The detector’s performance was also compared with that of an ionization chamber. The
-Ga
detector exhibited a linear response with proton dose for single-spot irradiations, and its response to varying proton energies closely matched both the ion chamber data and simulated dose distributions. These findings highlight the potential of
-Ga
-based detectors as robust dosimetry devices for IMPT applications.
Low thermal boundary resistance and reduced junction temperature in GaN HEMTs via AlN-mediated top-side diamond integration
Kexin Deng
et al
2026
Semicond. Sci. Technol.
41
045013
View article
, Low thermal boundary resistance and reduced junction temperature in GaN HEMTs via AlN-mediated top-side diamond integration
PDF
, Low thermal boundary resistance and reduced junction temperature in GaN HEMTs via AlN-mediated top-side diamond integration
Gallium nitride (GaN) high-electron-mobility transistors are constrained by localized self-heating, which compromises reliability and limits power scaling. While diamond integration offers a superior thermal management solution, minimizing the thermal resistance of the near-junction passivation layers remains a critical challenge. This work demonstrates an effective top-side thermal management strategy by fabricating a GaN/AlN/diamond heterostructure, replacing the conventional low-thermal-conductivity SiN passivation. Enabled by a thin AlN interlayer, this architecture achieves an ultra-low thermal boundary resistance of 6.5 m
·K GW
−1
. Consequently, under a high power density of 24 W mm
−1
, transient thermal analysis reveals a significant peak junction temperature reduction of ∼30 °C compared to standard SiN-passivated devices. Cross-sectional TEM and energy-dispersive x-ray spectroscopy confirm atomically abrupt interfaces without interdiffusion, validating the structural integrity. These results underscore the efficacy of eliminating the thermal barrier in the near-junction region, establishing a viable pathway for realizing the full potential of diamond-enhanced GaN electronics.
A novel double-channel sic trench MOSFET realized by integrating n-PolySi/sic heterojunction tunneling transistor
Bo Yi
et al
2026
Semicond. Sci. Technol.
41
045012
View article
, A novel double-channel sic trench MOSFET realized by integrating n-PolySi/sic heterojunction tunneling transistor
PDF
, A novel double-channel sic trench MOSFET realized by integrating n-PolySi/sic heterojunction tunneling transistor
In this article we propose a 600 V rated 4H-SiC trench MOSFET integrated with an n-PolySi/4H-SiC heterojunction tunneling transistor (named as nHJTT-MOS) and calibrated simulations are used to demonstrate the advantages of the proposal. The trench gate is semi-enclosed by n-PolySi and a heterojunction of n-PolySi/4H-SiC is formed. A P
shielding layer surrounding the n-PolySi is used to protect the pre-breakdown of PolySi and gate oxide. When
GS
is high, high electron densities accumulated on two sides of the n-PolySi/4H-SiC, which forms a low resistive channel for the electron tunneling current. Thus, much lower specific on-resistance (
on,sp
) can be obtained especially for 600 V rated SiC MOSFETs. In the reverse conduction state, the n-PolySi/4H-SiC heterojunction diode inactivates the PN body diode and the reverse on-state voltage (
R_on
) is significantly reduced. Calibrated simulations demonstrate that
on,sp
and
R_on
of nHJTT-MOS are only 0.73 mΩ·cm
and 0.84 V, which are reduced by 26.3% and 0.87 V compared with those of the p-PolySi-based trench MOSFET. The proposed nHJTT-MOS shows high potential for SiC trench MOSFET at the middle-low voltage level, in which the low channel mobility significantly hinders the reduction of
on,sp
Review of Ga
x-ray detectors: from material properties to device applications
Liru Zeng
et al
2026
Semicond. Sci. Technol.
41
043002
View article
, Review of Ga2O3 x-ray detectors: from material properties to device applications
PDF
, Review of Ga2O3 x-ray detectors: from material properties to device applications
Gallium oxide (Ga
) has emerged as a highly promising semiconductor material for next-generation x-ray detection, owing to its ultra-wide bandgap, high breakdown electric field, and strong x-ray absorption capability. This review systematically summarizes recent advances in Ga
-based x-ray detectors from the perspectives of material properties, device design, and practical applications. It begins by elucidating the intrinsic material characteristics of Ga
and their underlying physical mechanisms in x-ray detection. Then, it focuses on analyzing the performance of detectors based on different forms, including bulk single crystals, epitaxial thin films, amorphous films, and heterostructures, while addressing key challenges such as inefficient hole transport and deep-level defects along with corresponding mitigation strategies. Finally, the application prospects of Ga
detectors in cutting-edge fields such as imaging arrays and flexible sensors are discussed, and future research directions in material optimization, device structure design, and system integration are outlined.
Progress in
-Ga
growth and devices
Yangyang Gao
et al
2026
Semicond. Sci. Technol.
41
043001
View article
, Progress in ε/κ-Ga2O3 growth and devices
PDF
, Progress in ε/κ-Ga2O3 growth and devices
ε/κ
-Ga
has attracted increasing attention due to its ultra-wide bandgap, unique piezoelectric properties, and high lattice symmetry, demonstrating significant potential in applications such as solar-blind ultraviolet detectors and high-voltage or high-power devices. This review systematically summarizes recent advances in growth methods for high-quality
ε/κ
-Ga
films,
ε/κ
-Ga
-based alloys, and n-type
ε/κ
-Ga
thin films. Based on high-quality
ε/κ
-Ga
thin films, state-of-the-art
ε/κ
-Ga
devices have been fabricated, including solar-blind photodetectors, Schottky barrier diodes, heterojunction diodes, and metal–oxide-semiconductor field-effect transistors. Finally, we present perspectives on both the promising prospects and critical challenges facing
ε/κ
-Ga
research.
Recent advances in heterojunction engineering of
-Ga
-based solar-blind ultraviolet photodetectors
Yahan Wang
et al
2026
Semicond. Sci. Technol.
41
023002
View article
, Recent advances in heterojunction engineering of β-Ga2O3-based solar-blind ultraviolet photodetectors
PDF
, Recent advances in heterojunction engineering of β-Ga2O3-based solar-blind ultraviolet photodetectors
In recent years, the demand for high-performance photodetectors in environmental monitoring, specialized detection, and space communications has grown significantly. Solar-blind ultraviolet (SBUV) photodetectors have become a research hotspot due to their unique spectral selectivity and high sensitivity. As an ultra-wide bandgap semiconductor material (∼4.9 eV),
-Ga
is regarded as a highly promising material for SBUV detection owing to its excellent intrinsic properties, including high breakdown field strength, outstanding thermal stability, and superior response in the SBUV band. Research demonstrates that constructing
-Ga
-based heterojunctions effectively regulates interfacial band structures, significantly enhances photogenerated carrier separation efficiency, improves device responsivity while suppressing dark current, and offers potential pathways to address performance limitations of conventional photodetectors. Based on a coordinated material-device optimization framework, this review systematically summarizes recent research advances in
-Ga
heterojunction SBUV photodetectors, with a focus on performance optimization strategies from three dimensions: material property modulation, heterojunction interface engineering, and device structure design. Future development directions are also discussed.
Time dynamics of excitons in monolayers of transition metal dichalcogenides
Faiha Mujeeb and Subhabrata Dhar 2026
Semicond. Sci. Technol.
41
023001
View article
, Time dynamics of excitons in monolayers of transition metal dichalcogenides
PDF
, Time dynamics of excitons in monolayers of transition metal dichalcogenides
The review explores the recent studies carried out to understand various dynamical processes, such as the generation, diffusion, recombination, valley depolarization and decoherence of excitons in monolayers of transition metal dichalcogenides. The rate of recombination of excitons in this class of materials has been found to be several orders of magnitude more than in bulk and quantum well structures of conventional semiconductors. This has been attributed to tighter excitonic confinement and stronger Coulomb interaction due to reduced dielectric screening. Trions are found to have orders of magnitude longer life-time than excitons. Moreover, trions show several orders of magnitude longer valley depolarization and valley decoherence times than the neutral excitons. These features give trions an edge over the neutral excitons in terms of controllability of the valley pseudospin for applications in valley based electronics and quantum information processing. However, very little have been done so far to understand the dynamical aspects of trions. Since large area coverage of the monolayer films is necessary for any practical application, it is important to understand the influence of defects and strain on the time dynamics of excitons and their complexes. Unfortunately, only a few such systematic studies are so far been carried out. Various aspects of the dynamical phenomena of excitons are associated with the strong Coulomb interaction, which in principle can be controlled through capping the monolayer with appropriate dielectrics. Comprehensive investigations are needed to understand the effect of the dielectric environment on the timescales of different dynamical processes associated with the excitons and their complexes. Also, the studies of the dynamical aspects of bigger excitonic complexes, such as biexcitons and charged biexcitons, are still lacking. Since dark excitons are difficult to detect optically, their recombination and phase-coherence time-scales are yet to be explored. This knowledge may be helpful in utilizing these entities for future applications.
Advances in electrochemical interface regulation toward stable zinc anodes
Navpreet Kamboj
et al
2025
Semicond. Sci. Technol.
40
123001
View article
, Advances in electrochemical interface regulation toward stable zinc anodes
PDF
, Advances in electrochemical interface regulation toward stable zinc anodes
Aqueous zinc-ion batteries are gaining attention as a strong alternative to lithium-ion batteries due to their inherent safety, affordability, and the impressive theoretical capacity of zinc metal. However, their widespread use is currently limited by instabilities at the zinc/electrolyte interface, which manifest as excessive dendritic growth, unwanted side reactions, and irregular formation of solid electrolyte interphases (SEIs). These challenges contribute to rapid capacity loss, low Coulombic efficiency, and shorter cycle life. This review provides a comprehensive examination of contemporary interfacial engineering techniques aimed at regulating zinc ion (Zn
2+
) flow, balancing electric field distribution, and improving interfacial stability. It focuses on the structure and dynamic behavior of the SEI, emphasizing its critical role in managing ion transport and preserving the physical integrity of the battery. We analyze a variety of strategically designed interfacial structures, including carbon-based frameworks, zinc-attractive inorganic coatings (such as ZnF
and ZnO), MXene composites, and dielectrics. These solutions have demonstrated success in minimizing dendrite formation and improving cycling stability. Furthermore, we evaluate new approaches involving ferroelectric materials, amphiphilic triblock copolymers, and responsive liquid metal interfaces that could significantly advance zinc anode performance. This review aims to be a valuable resource that guides future research toward developing resilient, dendrite-resistant zinc anodes for high-performance and scalable energy storage solutions.
Investigation of Mechanical Properties and Dislocation Glide in Homoepitaxial and Heteroepitaxial Mg-doped GaN
Shu et al
View accepted manuscript
, Investigation of Mechanical Properties and Dislocation Glide in Homoepitaxial and Heteroepitaxial Mg-doped GaN
PDF
, Investigation of Mechanical Properties and Dislocation Glide in Homoepitaxial and Heteroepitaxial Mg-doped GaN
This study systematically investigates the mechanical properties and dislocation behavior in homoepitaxial and heteroepitaxial Mg-doped GaN. It is found that increasing the Mg doping concentration does not significantly enhance hardness or Young's modulus, contradicting the solid-solution hardening mechanism.Homoepitaxial samples exhibit a dislocation density two orders of magnitude lower than heteroepitaxial ones and demonstrate superior resistance to plastic deformation.Creep behavior approaches ideal plasticity, with a stress exponent n >> 8, indicating it is not governed by dislocation glide or climb. Cathodoluminescence mapping confirms that dislocation glide on the (0001) plane proceeds along the <11-20> directions, with Mg doping altering slip zone morphology in heteroepitaxial films. These findings provide key insights for designing durable GaN-based devices.
Enhanced Selective Etching of SiON Using Low-GWP C 3 F 6 as an Alternative to CF 4 in Low-Bias-Power Inductively Coupled Plasmas
Yang et al
View accepted manuscript
, Enhanced Selective Etching of SiON Using Low-GWP C 3 F 6 as an Alternative to CF 4 in Low-Bias-Power Inductively Coupled Plasmas
PDF
, Enhanced Selective Etching of SiON Using Low-GWP C 3 F 6 as an Alternative to CF 4 in Low-Bias-Power Inductively Coupled Plasmas
Silicon oxynitride (SiON) thin films are widely used as mask materials for amorphous carbon layer (ACL) patterning, where high etch selectivity and stable profile control are required. In this study, the etching characteristics of SiON mask layers were systematically investigated using C₃F₆/C₄F₈/He plasmas in a 2 MHz bias inductively coupled plasma (ICP) system, with direct comparison to conventional CF₄-based chemistry under ultra-low-pressure conditions. Despite its significantly lower global warming potential (GWP), the C₃F₆-based plasma exhibited SiON etch rates comparable to those of CF₄ while consistently providing enhanced selectivity to photoresist over a wide range of gas-mixing conditions. Representative cross-sectional SEM images confirmed that anisotropic and well-preserved SiON profiles were maintained, indicating that the improved selectivity was achieved without compromising profile integrity. Plasma diagnostics and surface analyses suggest that the enhanced selectivity originates from controlled fluorocarbon surface reactions without excessive polymer accumulation. In addition, exhaust-line FTIR analysis combined with mass-manufactured total CO₂ equivalent (MMTCE) evaluation revealed reduced greenhouse gas emission characteristics for the C₃F₆-based process compared to CF₄. These results indicate that C₃F₆ is a viable low-GWP alternative to CF₄ for SiON mask etching, offering improved selectivity, stable profile control, and reduced environmental impact in ACL-related fabrication processes.
Impact of Miscut Angles on Mechanical Properties and Surface Damage of (100) β-Ga₂O₃
Bi et al
View accepted manuscript
, Impact of Miscut Angles on Mechanical Properties and Surface Damage of (100) β-Ga₂O₃
PDF
, Impact of Miscut Angles on Mechanical Properties and Surface Damage of (100) β-Ga₂O₃
β-Ga2O3 is an emerging ultra-wide-bandgap semiconductor material with significant potential for power and optoelectronic devices. High-quality homoepitaxial growth plays a critical role in its device performance. While miscut angles on (100)-oriented substrates have been shown to promote step-flow mode in epitaxial growth methods such as MOCVD, their effects on mechanical properties and surface damage behavior remain unclear. In this study, β-Ga2O3 (100) substrates with miscut angles of 0°, 4°, and 6° were systematically investigated using nanoindentation, TEM, AFM, and wet chemical etching. The result indicates that the 6° miscut substrate exhibits a reduction in hardness by approximately 13%, to 8.31±0.36 GPa compared to ~9.57–9.78 GPa for 0° and 4°substrates. In contrast, the elastic modulus increases with bigger miscut angle. Under 1 mN load, both the 4° and 6° samples primarily deform via dislocations and stacking faults. The 4° miscut sample additionally shows the formation of an amorphous layer (α-phase regions), and near-surface (200) stacking faults. Surface morphology analysis reveals brittle removal with cleavage pits in 4° miscut substrate, whereas the 6° sample demonstrates ductile removal and lower defect density. These findings underscore the important influence of miscut angle on the mechanical response and surface integrity of β-Ga2O3 substrates. Providing insights for optimizing epitaxial growth and enhancing device performance.
The following article is
Open access
Influence of Aluminium Incorporation on the Semiconducting Properties of P-type Tin Monoxide
Peek et al
View accepted manuscript
, Influence of Aluminium Incorporation on the Semiconducting Properties of P-type Tin Monoxide
PDF
, Influence of Aluminium Incorporation on the Semiconducting Properties of P-type Tin Monoxide
Herein, we report the first TFTs using Sn(HMDS)
as a precursor for the atomic layer deposition of SnO. We subsequently, investigate the incorporation of Al-ions in the device channel, from three aluminium sources using low energy ion scattering. Alumina is widely exploited in the fabrication of p-type tin monoxide (SnO) thin film transistors. It has been used as a surface passivation, as a dopant, and as a substrate barrier layer. Alumina is a source of Al
3+
, which is a compensating donor in SnO. We demonstrate that the intentional incorporation of aluminium into SnO, by introducing alumina cycles during atomic layer deposition, has the effect of increasing the sheet resistance of the SnO films by 10
times and amorphising the film microstructure. Further, the incorporation of Al ions from alumina passivation-capping and barrier layers is revealed at their interfaces with the SnO TFT channel. The transfer characteristics of thin film transistors fabricated from the Al-doped and capped SnO films is used to show the effects of annealing, which are explained in terms of Al ion incorporation. Interdiffusion or incorporation of Al ions, into the SnO semiconductor, identified by depth profile low energy ion scattering, indicates that auto-doping plays a significant role in modifying the characteristics of SnO TFTs. The application of alumina layers in the design of p-type tin monoxide thin film transistors must take account of the influence of Al ion incorporation on the semiconducting properties of SnO.
Electro-Thermal Analysis of CFETs With a Dual-Substrate Architecture
Kim et al
View accepted manuscript
, Electro-Thermal Analysis of CFETs With a Dual-Substrate Architecture
PDF
, Electro-Thermal Analysis of CFETs With a Dual-Substrate Architecture
In complementary FET (CFET) architectures, the vertically stacked device configuration inherently limits heat dissipation paths, leading to severe self-heating effects (SHE), particularly in the upper device. This work presents an electro-thermal and reliability analysis of CFETs employing a dualsubstrate architecture, which provides an additional thermal conduction path to mitigate SHE. The proposed structure is quantitatively compared with nanosheet FETs (NS-FETs), monolithic CFETs (mCFETs), and sequential CFETs (sCFETs) under identical operating conditions using precisely calibrated 3D TCAD simulations. Electro-thermal simulation results show that, compared to the NS-FET, the dual-substrate CFET with a 30-nm top silicon layer reduces the maximum temperature rise (∆T
MAX
) and thermal resistance (R
TH
) from 60.3% and 76.3% in the conventional sCFET to 12.6% and 26.1%, respectively. To identify the optimal substrate thickness, a figure of merit (FoM), defined as the product of propagation delay and maximum temperature (T
MAX
), is introduced. The FoM reaches a minimum at a top substrate thickness of 30 nm, indicating the optimal performancethermal trade-off. Furthermore, device reliability is quantitatively evaluated in terms of hot-carrier injection (HCI) and bias temperature instability (BTI) lifetime models, showing 4.7× and 10.5× improvements, respectively, for the proposed CFET with a 30-nm additional substrate compared to the conventional sCFET. These results demonstrate that the proposed structure effectively alleviates SHE in CFETs and provides improved long-term device reliability for advanced logic applications.
More Accepted manuscripts
The following article is
Open access
Phosphorus vacancy as a dominant donor in n-InP single crystals grown by VGF method
Yihan Bai
et al
2026
Semicond. Sci. Technol.
41
045016
View article
, Phosphorus vacancy as a dominant donor in n-InP single crystals grown by VGF method
PDF
, Phosphorus vacancy as a dominant donor in n-InP single crystals grown by VGF method
S-doped and Fe-doped InP single crystals grown by vertical gradient freezing (VGF) method have been characterized and compared by density, lattice parameter, photoluminescence spectroscopy (PL), Hall effect and glow discharge mass spectroscopy measurements. The density of S-doped InP crystals decreases apparently with increasing carrier concentration, implying the existence of vacancy defects with high concentration. Most of the n-InP single crystals exhibit a much higher carrier concentration than the S doping concentration and a significant compensation from acceptors irrelevant to the impurity. Lattice parameter increases with the increase in carrier concentration of the n-type InP single crystals with practical S doping concentration close to each other. PL results demonstrate a donor defect with energy level above the conduction band bottom. These results are explained by the formation of both phosphorus vacancy and indium vacancy in the VGF growth process, acting as donor and acceptor in the n-InP single crystal, respectively. The presence of phosphorus vacancy defects with high concentration dominates the anomalous density variation in S-doped InP and has a significant impact on its electrical properties. The formation mechanism of vacancy defects is discussed based on the theory of defect thermodynamics and formation energy.
The following article is
Open access
Influence of Aluminium Incorporation on the Semiconducting Properties of P-type Tin Monoxide
Benjamin John Peek
et al
2026
Semicond. Sci. Technol.
View article
, Influence of Aluminium Incorporation on the Semiconducting Properties of P-type Tin Monoxide
PDF
, Influence of Aluminium Incorporation on the Semiconducting Properties of P-type Tin Monoxide
Herein, we report the first TFTs using Sn(HMDS)
as a precursor for the atomic layer deposition of SnO. We subsequently, investigate the incorporation of Al-ions in the device channel, from three aluminium sources using low energy ion scattering. Alumina is widely exploited in the fabrication of p-type tin monoxide (SnO) thin film transistors. It has been used as a surface passivation, as a dopant, and as a substrate barrier layer. Alumina is a source of Al
3+
, which is a compensating donor in SnO. We demonstrate that the intentional incorporation of aluminium into SnO, by introducing alumina cycles during atomic layer deposition, has the effect of increasing the sheet resistance of the SnO films by 10
times and amorphising the film microstructure. Further, the incorporation of Al ions from alumina passivation-capping and barrier layers is revealed at their interfaces with the SnO TFT channel. The transfer characteristics of thin film transistors fabricated from the Al-doped and capped SnO films is used to show the effects of annealing, which are explained in terms of Al ion incorporation. Interdiffusion or incorporation of Al ions, into the SnO semiconductor, identified by depth profile low energy ion scattering, indicates that auto-doping plays a significant role in modifying the characteristics of SnO TFTs. The application of alumina layers in the design of p-type tin monoxide thin film transistors must take account of the influence of Al ion incorporation on the semiconducting properties of SnO.
The following article is
Open access
Low-frequency noise analysis in dual δ-doped InGaAs quantum well micro Hall sensors with different doping concentrations andlocations
Chun-Yi Li
et al
2026
Semicond. Sci. Technol.
View article
, Low-frequency noise analysis in dual δ-doped InGaAs quantum well micro Hall sensors with different doping concentrations andlocations
PDF
, Low-frequency noise analysis in dual δ-doped InGaAs quantum well micro Hall sensors with different doping concentrations andlocations
We investigated the electric noise characteristics of Hall devices made with dual δ-doped InGaAs quantum wells by varying the doping concentration and location. The noise was studied in the frequency range from 0.1 Hz to 1 kHz at room temperature in a transverse configuration, with an active area of 140 × 140 μm^2. The Hooge parameter was found to be inversely proportional to the square of the carrier concentration, but independent of the doping location. Such significant reduction of noise, in comparison to the Hooge formula, was explained by the screening of potential modulation provided by the dual δ-doped layers. The results indicate the beneficial role of high carrier concentration in such type of device.
The following article is
Open access
a-plane GaN-based Fully Vertical FinFETs with Normally-off Operation
Navya Sri Garigapati
et al
2026
Semicond. Sci. Technol.
View article
, a-plane GaN-based Fully Vertical FinFETs with Normally-off Operation
PDF
, a-plane GaN-based Fully Vertical FinFETs with Normally-off Operation
In this work, the electrical performance of fully vertical single-fin a-plane GaN FinFETs with short gate length (L
≈ 200 nm) and a drift-layer thickness of 4.3 µm is investigated. Device characteristics are evaluated over a temperature range from 25 °C to 150 °C for various fin widths. The FinFETs exhibit stable normally-off operation across the entire temperature range. For a device with a fin width of 100 nm, a positive threshold voltage of 1.7 V is achieved and remains stable up to 150 °C. The same device demonstrates a specific on-resistance of 3 mΩ•cm
, a minimum subthreshold swing of 63 mV/dec, an ON/OFF current ratio of approximately 10
10
and a current density of 2.4 kA/cm
(133 kA/cm
when normalized to the single-fin active area, including current spreading in the drift layer). An increase in threshold voltage with temperature, particularly at 150 °C, is observed, indicating robust electrostatic control and favourable thermal stability for high-temperature power device operation.
The following article is
Open access
Dosimetry for proton therapy using a
-Ga
metal–semiconductor–metal detector with low-noise amplification
Hunter D Ellis
et al
2026
Semicond. Sci. Technol.
41
045014
View article
, Dosimetry for proton therapy using a β-Ga2O3 metal–semiconductor–metal detector with low-noise amplification
PDF
, Dosimetry for proton therapy using a β-Ga2O3 metal–semiconductor–metal detector with low-noise amplification
Intensity-modulated proton therapy (IMPT) employs proton radiation rather than conventional x-rays to treat cancerous tumors. This approach offers significant advantages by minimizing the radiation exposure of surrounding healthy tissue, leading to improved patient outcomes and reduced side effects compared to traditional x-ray therapy. To ensure patient safety, each treatment plan must be experimentally validated before clinical implementation. However, current dosimetry devices face limitations in performing angled beam measurements and obtaining multi-depth assessments, both of which are essential for verifying IMPT treatment plans. In this study, the performance of a
-Ga
-based metal–semiconductor–metal detector with a low-noise amplifier has been studied and evaluated under various proton radiation doses and energy levels delivered by a MEVION S250i proton accelerator. The detector’s performance was also compared with that of an ionization chamber. The
-Ga
detector exhibited a linear response with proton dose for single-spot irradiations, and its response to varying proton energies closely matched both the ion chamber data and simulated dose distributions. These findings highlight the potential of
-Ga
-based detectors as robust dosimetry devices for IMPT applications.
The following article is
Open access
Semiclassical theories of scattering mechanisms on 2DEG transport and the enhancement of electron mobility in Al(Ga)N/GaN heterostructures
Gongyi Hong
et al
2026
Semicond. Sci. Technol.
View article
, Semiclassical theories of scattering mechanisms on 2DEG transport and the enhancement of electron mobility in Al(Ga)N/GaN heterostructures
PDF
, Semiclassical theories of scattering mechanisms on 2DEG transport and the enhancement of electron mobility in Al(Ga)N/GaN heterostructures
Two-dimensional electron gases (2DEGs) play a central role in a wide range of electronic components. A thorough understanding of mobility-limiting scattering mechanisms is therefore crucial for the design of high-performance devices. In particular, with continuing device miniaturization, scattering processes such as interface roughness scattering increasingly influence the mobility of more confined 2DEGs. This paper reviews the theoretical treatment of the essential scattering mechanisms within the effective mass theory, along with the solution of the Boltzmann transport equation via linearization and the momentum relaxation time approximation. The calculation of total mobility is discussed, and recent theoretical predictions of mobility enhancement in AlN/GaN high electron mobility transistors (HEMTs) are highlighted.
The following article is
Open access
Temperature dependent characteristics of AlGaAsSb single photon avalanche diodes
Jonathan Taylor-Mew
et al
2026
Semicond. Sci. Technol.
41
045005
View article
, Temperature dependent characteristics of AlGaAsSb single photon avalanche diodes
PDF
, Temperature dependent characteristics of AlGaAsSb single photon avalanche diodes
Near-infrared single photon avalanche diodes (SPADs) are practical single photon detectors, particularly for applications requiring high operating temperatures. Compared to established InP SPADs, AlGaAsSb SPAD offers superior thermal stability but currently exhibit lower single photon detection efficiency. To improve their performance, origin(s) of AlGaAsSb SPAD’s dark count rate (DCR) and detection efficiency versus overbias characteristics should be investigated. We explore these by performing extensive DCR and SPDE measurements on InGaAs/AlGaAsSb SPADs in gated mode at relevant temperatures (200–290 K). The maximum SPDE at 1550 nm wavelength was 31 (4 V overbias) and 20% (3 V overbias) at 200 and 250 K, respectively, higher than earlier reports of AlGaAsSb SPADs. DCR data analyses show that the tunneling current is a dominant DCR mechanism over the range studied. It most likely originated from the InGaAs absorber, despite an attempt to reduce the electric field in the design. It is therefore necessary to ensure the entire InGaAs absorber does not experience a relatively high electric field in future designs of AlGaAsSb SPADs. If AlGaAsSb SPADs without tunneling current can be achieved, their single photon detection performance is expected to match that of InP SPADs at least, while exhibiting superior thermal stability.
The following article is
Open access
Bandgap engineering with carriers blocking in long-wavelength infrared photodiodes
Linxuan He
et al
2026
Semicond. Sci. Technol.
41
045002
View article
, Bandgap engineering with carriers blocking in long-wavelength infrared photodiodes
PDF
, Bandgap engineering with carriers blocking in long-wavelength infrared photodiodes
This document addresses the regulation of leakage current induced by composition-correlated bandgap depletion for novel bandgap gradient multilayer heterojunction (BGMH) Hg
1−
Cd
Te long-wavelength infrared (LWIR) photodiodes. The issue that the energy band barrier impedes the hole diffusion process is successfully eliminated by controlling the relative position of the electric field and the heterojunction material. Here, the technology computer-aided design (TCAD)-based device model is employed to verify the energy band distribution, and several means, including pre-etching before doping and reducing absorber-layer concentration, are proposed to optimize the device performance. Consequently, the ‘turn-on’ bias (|
to
|) required for the device to transition into a diffusion-dominated is reduced from 1.2 V to less than 0.2 V. Finally, an 11.5
m LWIR BGMH device is utilized to confirm the proposed model and enhanced quantum efficiency from 33.2% to 70.0%, which can effectively support engineering applications.
The following article is
Open access
Multi-beam interference in GaN epitaxial layer thickness measurement: impact analysis and method optimization
Dongsheng He
et al
2026
Semicond. Sci. Technol.
View article
, Multi-beam interference in GaN epitaxial layer thickness measurement: impact analysis and method optimization
PDF
, Multi-beam interference in GaN epitaxial layer thickness measurement: impact analysis and method optimization
Addressing the critical demand for high-precision metrology of GaN epitaxial layers on SiC substrates, this study presents a rigorous mid-infrared reflectance methodology integrating physical modeling with global optimization. The complex infrared dispersion of GaN is accurately characterized using the Drude-Lorentz dielectric function, while the Airy multi-beam interference theory is employed to rectify systematic errors inherent in traditional dual-beam approximations. To tackle the non-convex optimization landscape caused by multi-beam interference, a spectral inversion strategy utilizing the Simulated Annealing (SA) algorithm is developed. This approach effectively escapes local minima traps—a common failure point in gradient-based methods—and achieves global convergence by minimizing the full-spectrum Residual Sum of Squares (RSS). The physical consistency of the model is validated through angle-resolved reflectance mapping, confirming exceptional robustness against optical path variations. Furthermore, a comprehensive uncertainty evaluation, incorporating parameter sensitivity analysis, correlation matrices, and Monte Carlo simulations, demonstrates the effective decoupling of thickness from dielectric parameters. Notably, unlike classical interferometry, this method enables the simultaneous extraction of thickness and electrical properties.The results yield a thickness measurement result of 5.32±0.17μm (coverage factor k=2), providing a robust, non-destructive solution for the precision metrology of Group III nitride thin films.
The following article is
Open access
A wearable bionic robotic controller based upon a printed silver nanosheets force-sensing resistor
Ping-Hui Lee
et al
2026
Semicond. Sci. Technol.
View article
, A wearable bionic robotic controller based upon a printed silver nanosheets force-sensing resistor
PDF
, A wearable bionic robotic controller based upon a printed silver nanosheets force-sensing resistor
A force-sensing resistor (FSR) consists of printed conducting ink layered on a flexible substrate, with resistance that changes in response to external force, which shown compact, easy to replace, affordable, and suitable for experimental applications. However, the inherent characteristics of FSR architectures present critical challenges, including nonlinear restoring forces, limited durability in harsh environments, and low integration density, which hinder their practical deployment in industrial settings. In this study, remote control of a 3D-printed prosthetic hand based on an FSR integrated with designed circuitry is demonstrated, exhibiting excellent operational stability. The relationship between external force and FSR resistance is monitored within the linear region by a control module that forms a closed circuit using an Arduino microcontroller, the FSR, a battery, and a reference resistor.Additionally, the servomotor is directly driven by the control module, with its angle of rotation dependent on the linearly calibrated FSR signal. Finally, the finger joint synchronizes with the servomotor and FSR signal, utilizing the calibration curve to translate the external force detected by the FSR into a control signal that drives the servomotor to rotate the finger joint structure. These results highlight the significant potential of the FSR integration module for next-generation bionic robotic control and provide a solid foundation for applications in augmented reality and artificial intelligence (AI).
More Open Access articles
Recent progress in Ga
power devices
Masataka Higashiwaki
et al
2016
Semicond. Sci. Technol.
31
034001
View article
, Recent progress in Ga2O3 power devices
PDF
, Recent progress in Ga2O3 power devices
This is a review article on the current status and future prospects of the research and development on gallium oxide (Ga
) power devices. Ga
possesses excellent material properties, in particular for power device applications. It is also attractive from an industrial viewpoint since large-size, high-quality wafers can be manufactured from a single-crystal bulk synthesized by melt–growth methods. These two features have drawn much attention to Ga
as a new wide bandgap semiconductor following SiC and GaN. In this review, we describe the recent progress in the research and development on fundamental technologies of Ga
devices, covering single-crystal bulk and wafer production, homoepitaxial thin film growth by molecular beam epitaxy and halide vapor phase epitaxy, as well as device processing and characterization of metal–semiconductor field-effect transistors, metal–oxide–semiconductor field-effect transistors and Schottky barrier diodes.
If it’s pinched it’s a memristor
Leon Chua 2014
Semicond. Sci. Technol.
29
104001
View article
, If it’s pinched it’s a memristor
PDF
, If it’s pinched it’s a memristor
This paper presents an in-depth review of the
memristor
from a rigorous
circuit-theoretic
perspective, independent of the material the device is made of. From an experimental perspective, a memristor is best defined as any two-terminal device that exhibits a
pinched hysteresis loop
in the voltage
current plane when driven by
any
periodic voltage or current signal that elicits a periodic response of the same frequency. This definition greatly broadens the scope of memristive devices to encompass even non-semiconductor devices, both organic and inorganic, from many unrelated disciplines, including biology, botany, brain science, etc. For pedagogical reasons, the broad terrain of memristors is partitioned into three classes of increasing generality, dubbed
Ideal Memristors
Generic Memristors
, and
Extended Memristors
. Each class is distinguished from the others via unique
fingerprints and signatures.
This paper clarifies many confusing issues, such as non-volatility, dc
V–I
curves, high-frequency
v–i
curves, local activity, as well as nonlinear dynamical and bifurcation phenomena that are the hallmarks of memristive devices. Above all, this paper addresses several fundamental issues and questions that many memristor researchers do not comprehend but are afraid to ask.
THz imaging and sensing for security applications—explosives, weapons and drugs
John F Federici
et al
2005
Semicond. Sci. Technol.
20
S266
View article
, THz imaging and sensing for security applications—explosives, weapons and drugs
PDF
, THz imaging and sensing for security applications—explosives, weapons and drugs
Over the past 5 years, there has been a significant interest in employing terahertz (THz) technology, spectroscopy and imaging for security applications. There are three prime motivations for this interest: (a) THz radiation can detect concealed weapons since many non-metallic, non-polar materials are transparent to THz radiation; (b) target compounds such as explosives and illicit drugs have characteristic THz spectra that can be used to identify these compounds and (c) THz radiation poses no health risk for scanning of people. In this paper, stand-off interferometric imaging and sensing for the detection of explosives, weapons and drugs is emphasized. Future prospects of THz technology are discussed.
Transparent conducting oxide semiconductors for transparent electrodes
Tadatsugu Minami 2005
Semicond. Sci. Technol.
20
S35
View article
, Transparent conducting oxide semiconductors for transparent electrodes
PDF
, Transparent conducting oxide semiconductors for transparent electrodes
The present status and prospects for further development of polycrystalline or amorphous transparent conducting oxide (TCO) semiconductors used for practical thin-film transparent electrode applications are presented in this paper. The important TCO semiconductors are impurity-doped ZnO, In
and SnO
as well as multicomponent oxides consisting of combinations of ZnO, In
and SnO
, including some ternary compounds existing in their systems. Development of these and other TCO semiconductors is important because the expanding need for transparent electrodes for optoelectronic device applications is jeopardizing the availability of indium-tin-oxide (ITO), whose main constituent, indium, is a very expensive and scarce material. Al- and Ga-doped ZnO (AZO and GZO) semiconductors are promising as alternatives to ITO for thin-film transparent electrode applications. In particular, AZO thin films, with a low resistivity of the order of 10
−5
Ω cm and source materials that are inexpensive and non-toxic, are the best candidates. However, further development of the deposition techniques, such as magnetron sputtering or vacuum arc plasma evaporation, as well as of the targets is required to enable the preparation of AZO and GZO films on large area substrates with a high deposition rate.
Wide-bandgap semiconductor ultraviolet photodetectors
E Monroy
et al
2003
Semicond. Sci. Technol.
18
R33
View article
, Wide-bandgap semiconductor ultraviolet photodetectors
PDF
, Wide-bandgap semiconductor ultraviolet photodetectors
Industries such as the automotive, aerospace or military, as well as environmental and biological research have promoted the development of ultraviolet (UV) photodetectors capable of operating at high temperatures and in hostile environments. UV-enhanced Si photodiodes are hence giving way to a new generation of UV detectors fabricated from wide-bandgap semiconductors, such as SiC, diamond, III-nitrides, ZnS, ZnO, or ZnSe. This paper provides a general review of latest progresses in wide-bandgap semiconductor photodetectors.
-Ga
for wide-bandgap electronics and optoelectronics
Zbigniew Galazka 2018
Semicond. Sci. Technol.
33
113001
View article
, β-Ga2O3 for wide-bandgap electronics and optoelectronics
PDF
, β-Ga2O3 for wide-bandgap electronics and optoelectronics
-Ga
is an emerging, ultra-wide bandgap (energy gap of 4.85 eV) transparent semiconducting oxide, which attracted recently much scientific and technological attention. Unique properties of that compound combined with its advanced development in growth and characterization place
-Ga
in the frontline of future applications in electronics (Schottky barrier diodes, field-effect transistors), optoelectronics (solar- and visible-blind photodetectors, flame detectors, light emitting diodes), and sensing systems (gas sensors, nuclear radiation detectors). A capability of growing large bulk single crystals directly from the melt and epi-layers by a diversity of epitaxial techniques, as well as explored material properties and underlying physics, define a solid background for a device fabrication, which, indeed, has been boosted in recent years. This required, however, enormous efforts in different areas of science and technology that constitutes a chain linking together engineering, metrology and theory. The present review includes material preparation (bulk crystals, epi-layers, surfaces), an exploration of optical, electrical, thermal and mechanical properties, as well as device design/fabrication with resulted functionality suitable for different fields of applications. The review summarizes all of these aspects of
-Ga
at the research level that spans from the material preparation through characterization to final devices.
Metal oxide nanostructures for sensor applications
D Nunes
et al
2019
Semicond. Sci. Technol.
34
043001
View article
, Metal oxide nanostructures for sensor applications
PDF
, Metal oxide nanostructures for sensor applications
Human health, environmental protection and safety are just a few examples of humankind’s current main concerns, that drive the scientific community to develop sensors able to monitor precisely and provide alerts of possible harm in real time. Over the years, semiconductor metal oxide-based materials have been extensively employed as sensors in several applications. They are of particular interest at the nanometer scale, since it is widely known that a smaller crystallite size enhances a sensor’s performance. Moreover, these materials are highly appealing as they can be produced by low-cost wet-chemical synthesis routes and are in general nontoxic, earth abundant and low cost. This manuscript extensively reviews the recent developments of nanostructured semiconductor metal oxide sensors ranging from gas to humidity sensors, including ultraviolet sensors and biosensors. Sensors based on zinc oxide (ZnO), titanium dioxide (TiO
), tungsten trioxide (WO
), copper oxide (CuO and Cu
O), tin oxide (SnO and SnO
) and vanadium oxide (VO
and V
), either as nanoparticles or as continuous films or layers, are described. Their sensing properties are correlated to size, shape, presence of defects and doping elements, amongst other relevant parameters. Various techniques and methods of fabricating these materials are addressed. The review concludes with novel approaches for functionalization and future perspectives for sensor developments.
Review of SiC crystal growth technology
Peter J Wellmann 2018
Semicond. Sci. Technol.
33
103001
View article
, Review of SiC crystal growth technology
PDF
, Review of SiC crystal growth technology
The review article describes the interplay of fundamental research and advanced processes that have made SiC a unique semiconductor material for power electronic devices. Related to the outstanding physical properties of SiC, the preparation of this material is quite challenging. Processing is carried out at elevated temperatures that require special emphasis on the design of the growth machine and the applied construction materials. Growth inside a closed growth chamber demands the usage of advanced sensors and sophisticated computer simulation of the growth process. The application of advanced 2D and 3D
in situ
x-ray visualization techniques enables the visualization of the growth process. Reduction of the density of structural defects, a prerequisite for the technical application in power electronic devices, based on fundamental research and understanding of the crystallographic as well as the electronic properties of SiC beyond the knowledge base of standard semiconductor materials.
Half-Heusler compounds: novel materials for energy and spintronic applications
F Casper
et al
2012
Semicond. Sci. Technol.
27
063001
View article
, Half-Heusler compounds: novel materials for energy and spintronic applications
PDF
, Half-Heusler compounds: novel materials for energy and spintronic applications
Half-Heusler compounds are an impressive class of materials with a huge potential for different applications such as future energy applications and for spintronics. The semiconducting Heusler compounds can be identified by the number of valence electrons. The band gap can be tuned between 0 and 4 eV by the electronegativity difference of the constituents. Magnetism can be introduced in these compounds by using rare-earth elements, manganese or ‘electron’ doping. Thus, there is a great interest in the fields of thermoelectrics, solar cells and diluted magnetic semiconductors. The combination of different properties such as superconductivity and topological edge states leads to new multifunctional materials, which have the potential to revolutionize technological applications. Here, we review the structure, the origin of the band gap and the functionalities of semiconducting half-Heusler compounds.
Introduction to topological superconductivity and Majorana fermions
Martin Leijnse and Karsten Flensberg 2012
Semicond. Sci. Technol.
27
124003
View article
, Introduction to topological superconductivity and Majorana fermions
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, Introduction to topological superconductivity and Majorana fermions
This short review paper provides a pedagogical introduction to the rapidly growing research field of Majorana fermions in topological superconductors. We first discuss in some detail the simplest ‘toy model’ in which Majoranas appear, namely a one-dimensional tight-binding representation of a p-wave superconductor, introduced more than 10 years ago by Kitaev. We then give a general introduction to the remarkable properties of Majorana fermions in condensed matter systems, such as their intrinsically non-local nature and exotic exchange statistics, and explain why these quasiparticles are suspected to be especially well suited for low-decoherence quantum information processing. We also discuss the experimentally promising (and perhaps already successfully realized) possibility of creating topological superconductors using semiconductors with strong spin–orbit coupling, proximity-coupled to standard s-wave superconductors and exposed to a magnetic field. The goal is to provide an introduction to the subject for experimentalists or theorists who are new to the field, focusing on the aspects which are most important for understanding the basic physics. The text should be accessible for readers with a basic understanding of quantum mechanics and second quantization, and does not require knowledge of quantum field theory or topological states of matter.
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1986-present
Semiconductor Science and Technology
doi: 10.1088/issn.0268-1242
Online ISSN: 1361-6641
Print ISSN: 0268-1242