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Constructing nanoheterojunction is a crucial approach to achieving self-powered ultraviolet photodetectors based on Ga2O3. Two-dimensional modified NiS2 nanosheets are excellent candidates for fabricating nanoheterojunctions due to their high electrical conductivity for efficient charge transport, large surface area for enhanced light absorption, and exceptional chemical and thermal stability for reliable long-term UV detection. Herein, two-dimensional bimetallic (Co, Ni)-S2 nanosheets are proposed using a two-step hydrothermal synthesis method. Subsequently, a 3D/2D Ga2O3@(Co, Ni)-S2 heterojunction is constructed by depositing (Co, Ni)-S2 nanosheets onto the Ga2O3 nanowire network. Ga2O3@(Co, Ni)-S2 heterojunction photodetector achieves a self-driven responsivity of 36.56 mA W1– under 254 nm illumination, which is higher than the heterojunction photodetector based on Ga2O3 and monometallic NiS2 photodetector. Under 10 V bias, Ga2O3@(Co, Ni)-S2 heterojunction photodetector exhibits a high responsivity, detectivity, and external quantum efficiency of 1.51 A W1–, 7.68 × 1012 Jones, and 738.27%, which are 174.11, 8.95, and 174.11 times greater than those of pure Ga2O3 photodetector. The Ga2O3@(Co, Ni)-S2 photodetector also displays a faster response speed than that of the pure Ga2O3 photodetector. Calculated charge density differences show that improved performances are attributed to the advanced band alignment and interface charge transfer by forming the type I heterostructure between Ga2O3 and (Co, Ni)-S2. The established built-in electric field and lower Schottky barrier facilitate the effective transfer of photoelectrons at the nanointerface. Furthermore, the enhanced light absorption capacity and elevated conductivity of (Co, Ni)-S2 contribute to the improved photoelectric conversion capability. This research highlights that 2D bimetallic sulfide nanomaterials play a significant role in developing Ga2O3-based self-driven photodetectors. [ABSTRACT FROM AUTHOR]

Gallium oxide (Ga2O3) is an emerging and promising candidate for high-power and radiation-rich environments, such as space, thanks to its ultra-wide bandgap (~ 4.9 eV) and high critical electrical field (~ 8 MV/cm). Radiation in space, such as protons, alpha particles and heavy ions, can cause serious damage to electronic devices and even lead to permanent damage. However, assessing these devices' reliability and radiation hardness in space-like environments is often expensive and complex. In the present work, we utilize a technology computer-aided design (TCAD) simulation-based framework that uses the concept of non-ionizing energy loss (NIEL) to evaluate the displacement damage in electronic devices under particle irradiation. To assess the radiation tolerance of Ga2O3 diodes, first, a TCAD model for Ga2O3 Schottky barrier diodes (SBD) is developed and calibrated/benchmarked to an experimental device, followed by irradiation simulations. The results show that Ga2O3 SBD can withstand a 5 MeV proton fluence of ~ 1015 cm−2 with no change in the forward current voltage (IV) characteristics. This value is significantly higher than that of 4H-SiC (~5 × 1013 cm−2) and Si (~1 × 1012) SBDs with the same ideal breakdown voltage - VBR (1600 V), demonstrating the potential of Ga2O3 as a radiation-hard technology. [ABSTRACT FROM AUTHOR]

Plasmonic nanoarray structures offer great potential for high-performance photodetectors due to their excellent ability to effectively trap light. In this work, Ga2O3 solar-blind photodetectors with Ru nanogratings were designed, precisely fabricated, and characterized systematically for the first time. The Ru nanograting through localized surface plasmon resonance significantly concentrates the optical field, reduces the transmittance, and enhances light–matter interactions, ultimately increasing absorbance. Integrating the Ru nanograting into Ga2O3 films induces a blue shift in the response peak, from 245 nm in Ga2O3 films to 215 nm. Meanwhile, the peak current rises dramatically from 4.9 × 10–11 to 1.3 × 10–9 A. The peak responsivity and specific detectivity are increased by 4.9 × 102 times and 6.8 × 102 times, respectively. This modification also accelerates the response speed, with τr and τd, of 0.96/0.14 s, notably shorter than the 1.57/0.47 s in Ga2O3 films. The mechanisms underlying strengthened absorbance and light–matter interactions are comprehensively explained through both simulated and experimental data. This work lays the theoretical and experimental groundwork for future high-performance Ga2O3-based photodetectors. [ABSTRACT FROM AUTHOR]

This study explores the potential of 700‐nm‐thick heteroepitaxial α‐Ga2O3 thin films on c‐plane sapphire substrates for X‐ray detector applications. The crystal quality and optical bandgap of the heteroepitaxial α‐Ga2O3 thin films are comparable to those of high‐quality α‐Ga2O3 thin films. The α‐Ga2O3 thin film X‐ray detector with a metal–semiconductor–metal structure exhibits a charge neutral point shift, resulting in a short‐circuit current density of 9.07 nA cm−2 and an open‐circuit voltage of –1.2 V. The detector achieves the highest signal‐to‐noise ratio of 973 at 0 V, while the maximum sensitivity (14.7 μC Gyair−1 cm−2) occurs at 10 V. The proposed X‐ray detector demonstrates a reliable transient response and long‐term robustness, suggesting the promise of heteroepitaxial α‐Ga2O3 for low‐cost, high‐quality, large‐area X‐ray detectors. [ABSTRACT FROM AUTHOR]

A charge trapping layer (CTL) technique is incorporated to achieve a normally-off Ga2O3 MOSFET. The gate dielectric was engineered using a stack composed of a blocking layer (16 nm ${\mathrm { HfO}}_{\mathrm { x}}$ / 2 nm Al2O3), a CTL (5.76 nm Al:HfO ${_{\text {x}}}~1$ :5), and a tunneling barrier (2 nm Al2O3 / 2 nm ${\mathrm { HfO}}_{\mathrm { x}}$ / 2 nm Al2O3). The trap profile of the CTL layer and the interface of the gate dielectric and Ga2O3 channel are studied by photon-stimulated characterization, which yield highly uniform results, indicating the high quality and uniformity of the proposed method. Furthermore, we conducted a time-dependent dielectric breakdown (TDDB) test on devices both without a field plate (NOFP) and with a source-connected field plate (SFP) to investigate the dielectric failure mechanism and gain valuable insights for the design of CTL-based Ga2O3 MOSFETs.

Abstract Photodetectors play a crucial role in converting light signals into electrical signals and have significant applications in various fields such as communications, imaging, and sensing. However, the fabrication of a photodetector is a complex process that involves precise control of surface preparation, lithography, and deposition techniques. Here the study demonstrates that GaN/Ga2O3 heterojunctions can be fabricated utilizing laser processing to transform the surface of GaN into Ga2O3. The GaN/Ga2O3 heterojunctions exhibit good reproducibility, uniformity, and ability to operate under zero bias, with a responsivity of 110.22 mA W−1, a detection rate of 5.56 × 1011 jones, and an external quantum efficiency of 42.34%. Moreover, an 8 × 8 photodetector array based on GaN/Ga2O3 heterojunction is fabricated via laser writing and is demonstrated to have ultraviolet imaging capabilities. This report presents the pioneering fabrication of a photodetector array using laser writing. The findings offer a versatile and scalable approach for the production of large‐area heterojunction photodetector arrays.

Abstract The structural and electrical properties of undoped and Sn doped κ‐Ga2O3 layers grown by epitaxial lateral overgrowth on TiO2/sapphire substrates using stripe and point masks show that the crystalline structure of the films can be greatly improved relative to conventional planar growth. The undoped films are semi‐insulating, with the Fermi level pinned near EC‐0.7 eV, and deep electron traps at EC‐0.5 eV and EC‐0.3 eV are detectable in thermally stimulated current and photoinduced current transient spectra measurements. Low concentration Sn doping results in net donor concentrations of ≈ 1013 cm−3, and deep trap spectra determined by electron traps at EC‐0.5 eV, and deep acceptors with an optical ionization threshold near 2 and 3.1 eV. Treatment of the samples in hydrogen plasma at 330 °C increases the donor density near the surface to ≈ 1019 cm−3. Such samples show strong persistent photocapacitance and photoconductivity, indicating the possible DX‐like character of the centers involved. For thin (5 µm) κ‐Ga2O3 films grown on GaN/sapphire templates, p‐type‐like behavior is unexpectedly observed in electrical properties and we discuss the possible formation of a 2D hole gas at the κ‐Ga2O3/GaN interface.

Abstract Gallium oxide (Ga2O3) is an emerging ultra‐wide bandgap (UWBG) semiconductor material that has gained significant attention in the field of high voltage and high frequency power electronics. Its noteworthy attributes include a large bandgap (Eg) of 4.8 eV, high theoretical critical breakdown field strength (EC) of 8 MV cm−1, and saturation velocity (νs) of 2 × 107 cm s−1, as well as high Baliga figures of merit (BFOM) of 3000. In addition, Ga2O3 has the advantages of large‐size substrates that can be achieved by low‐cost melt‐grown techniques. This review provides a partial overview of pivotal milestones and recent advancements in the Ga2O3 material growth and device performance. It begins with a discussion of the fundamental material properties of Ga2O3, followed by a description of substrate growth and epitaxial techniques for Ga2O3. Subsequently, the contact technologies between Ga2O3 and other materials are fully elucidated. Moreover, this article also culminates with a detailed analysis of Ga2O3‐based high voltage and high frequency power devices. Some challenges and solutions, such as the lack of p‐type doping, low thermal conductivity, and low mobility are also presented and investigated in this review.

Abstract High‐temperature in situ growth of Ga2O3 thin film on flexible substrates for flexible/portable electronic devices is never realized because the conventional polymer substrates cannot meet the thermal‐stability requirements. In the research, for the first time, Ga2O3 thin films are directly grown on SiOx/Al2Ox buffered Hastelloy substrates. With pulsed laser deposition under high temperature, as‐grown Ga2O3 thin films have a fabric texture with a preferred out‐of‐plane orientation along (−201) and a good field‐effect mobility of 18.07 cm2 V−1 s−1. The Ga2O3 coated tape is patterned with transistor arrays and exhibited good performance homogeneity. The representative transistor devices have a threshold voltage of ≈−2.75 V and a breakdown voltage of 116 V measured under a −20 V gate voltage. Moreover, the tape transistors also have good mechanical robustness. The transistors’ good electrical performance, high uniformity, and mechanical robustness suggest that the in situ deposition technique using Hastelloy tape is promising for fabricating various flexible Ga2O3 channeled electronic circuits. Furthermore, it is believed that this technique can be extended to other flexible semiconductor devices that require high‐temperature processing.

Abstract The fabrication and characterization of metal/BaTiO3/β‐Ga2O3 solar‐blind photodetectors are reported. β‐Ga2O3 is a promising material for solar‐blind photodetectors due to its large bandgap and the availability of low defect‐density melt‐grown substrates. In this work, structures are introduced that employ high‐permittivity dielectric/semiconductor heterojunctions to enhance the performance of a Schottky photodetector. It is shown that integrating the high‐k dielectric BaTiO3 reduces the dark current by ≈104, all but eliminates illumination induced Schottky barrier lowering, and increases the UV–vis rejection ratio by a factor greater than 9 × 103 compared to a Schottky photodetector. It is hypothesized that the high permittivity of the dielectric overcomes the influence of self‐trapped holes in Ga2O3 to reduce the peak electric field at the dielectric/metal interface, thereby eliminating the effects of Schottky barrier lowering on illuminated β‐Ga2O3 photodetectors. Additionally, it is hypothesized that the increase in the UV–vis rejection ratio is caused by the “dead layer” that forms at the BaTiO3/Pt interface.

• Good crystallinity and growth quality of the Ga 2 O 3 and AlN thin films, with smooth surfaces and distinct boundaries, and some content of Ga 2 O 3 transitions from ε phase to β phase after inserting AlN interlayer. • A wider band gap of the heterostructure after adding the AlN interlayer, with low error ranges and high data reliability. • Notable improvement of thermal conductivity of Ga 2 O 3 films and of thermal boundary conductivity between the interface due to the AlN interlayer. Integration of gallium oxide (Ga 2 O 3) with highly thermal conductive AlN/sapphire substrate is more effective to dissipate heat in the Ga 2 O 3 -based devices. In this work, the properties of Ga 2 O 3 films grown on sapphire and AlN/sapphire substrates via MOCVD were both examined via various experimental methods. The X-ray diffraction (XRD) analysis showed good crystallinity and different orientations of Ga 2 O 3 and AlN thin films. The absorption properties and band gaps were extracted from UV/Vis spectra. The atomic force microscopy (AFM) scanning images showed smooth Ga 2 O 3 surfaces on sapphire and AlN/sapphire substrates (RMSs of 2.4 nm and 4.8 nm, respectively). The scanning electron microscopy (SEM) highlighted well-defined grains of Ga 2 O 3 and distinct boundaries of both heterostructures. X-ray photoelectron spectroscopy (XPS) analysis depicted the distributions of various components throughout the films. Finally, by using the time-domain thermoreflectance (TDTR) method, the thermal conductivity and the thermal boundary conductivity of Ga 2 O 3 without AlN interlayer were found to be 3.1 W/(m·K) and 70.1 MW/(m2·K) respectively. By comparison, adding AlN interlayer made the thermal conductivity and thermal boundary conductivity rise to 3.3 W/(m·K) and 111.5 MW/(m2·K) respectively. These findings have demonstrated the high-quality Ga 2 O 3 /AlN integration and good heat dissipation provided by AlN interlayer, opening up new prospects for Ga 2 O 3 /AlN devices in the future. [ABSTRACT FROM AUTHOR]

Radiation detectors have gained significant attention due to their extensive applications in high-energy physics, medical diagnostics, aerospace, and nuclear radiation protection. Advances in relevant technologies have made the drawbacks of traditional semiconductor detectors, including high leakage currents and instability, increasingly apparent. Ga₂O₃, diamond, and BN represent a new generation of semiconductor materials following GaN and SiC, offering wide bandgaps of around 5 eV. These ultra-wide bandgap (UWBG) semiconductors demonstrate excellent properties, including ultra-low dark current, high breakdown fields, and superior radiation tolerance, underscoring their promising potential in radiation detection. In this review, we first discuss the materials and electrical properties of Ga₂O₃, diamond, and BN, along with the general performance metrics relevant to radiation detectors. Subsequently, the review provides a comprehensive overview of the research progress in X-ray detection, charged particle detection (e.g., α particles and carbon ions), as well as fast neutron and thermal neutron detection, focusing on aspects such as chip fabrication processes, device architectures, and testing results for radiation detectors based on these three materials., (© 2025 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)