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Self-Powered Solar-Blind Photodetectors Based on <i>?±</i> / <i>?2</i> Phase Junction of
摘要： Self-powered Ga2O3-based solar-blind photodetectors have received attention recently due to the increased demand for energy saving, miniaturization, and high efficiency in devices. An ideal device structure consisting of a Ga2O3-based p-n junction is still difficult to obtain, since p-type doping is a major challenge. Although self-powered devices based on heterojunction are promising, there are two fatal disadvantages: (1) photosensitivity of the non-solar-blind region, on account of the narrower band gap of the heterojunction materials; and (2) poor quality of the epitaxial film due to lattice mismatch. In view of the various polymorphs of Ga2O3, we propose constructing a structure consisting of a Ga2O3 phase junction with α and β phases (α/β phase junction) for self-powered solar-blind photodetectors. The small lattice mismatch and similar band gap between α- and β-Ga2O3 will solve the two problems outlined above. The formation of α- and β-Ga2O3 is expected to result in a type-II band alignment, promoting separation of photogenerated carriers, which transfer through the junction to the corresponding electrodes. Herein, the α/β phase junction of Ga2O3 vertically aligned nanorod arrays with a thickness-controllable β-Ga2O3 shell layer are fabricated by a low-cost and simple process of hydrothermal and postannealing treatment. Two different types of self-powered α/β-Ga2O3 phase junction-based photodetectors, in the form of solid-state type and photoelectrochemical type, are constructed and realized. Our analysis shows that the constructed photodetectors are capable of highly efficient detection of solar-blind signal without any bias voltage. This work demonstrates the usefulness of using the α/β-Ga2O3 phase junction in a self-powered solar-blind photodetector, which is not only energy efficient, but also potentially workable in outer space, at the south and north pole, and other harsh environments without external power for a long time.
关键词： solar-blind photodetectors,phase junction,Ga2O3,α/β phase junction,self-powered
更新于2025-09-23 15:19:57
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High Sensitivity and Fast Response Self-Powered Solar-Blind Ultraviolet Photodetector with ?2-Ga2O3/Spiro-MeOTAD p-n Heterojunction
摘要： Solar-blind ultraviolet (UV) photodetectors are greatly desired in number of areas in terms of the military and civilian purposes, especially self-powered devices driven by the photovoltaic effect. Herein, a solar blind photodetector has been successfully achieved on a Spiro-MeOTAD/β-Ga2O3 organic-inorganic hybrid construction. The fabricated photodetector can operate with self-powered mode and show an obvious photodetection with a narrow spectrum region, exhibiting a high responsivity (65 mA/W) and a large external quantum efficiency (32％) under low power intensity (~1 μW/cm2) UV illumination, at zero bias. Fortunately, the device shows a fast temporal pulse response (τrise~2.98 μs and τdecay~28.49 μs), which is superior to the previously reported Ga2O3 based self-powered photodetectors. More importantly, the photodetector can operate stably and shows good repeatability. These excellent performances of device could be attributed to the pre-existing band alignment of the Ga2O3 and Spiro-MeOTAD, and are comparable to and/or even higher than those of other self-powered solar-blind UV photodetectors, which indicate that the design of device configuration based on a Ga2O3/Spiro-MeOTAD heterojunction is certified as an excellent candidate for high sensitivity, ultrafast response and self-powered photo-detecting device for solar-blind UV signal.
关键词： β-Ga2O3,Spiro-MeOTAD,photodetector,Solar-blind ultraviolet,self-powered,heterojunction
更新于2025-09-23 15:19:57
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[IEEE 2019 FISE-IEEE/CIGRE Conference - Living the energy Transition (FISE/CIGRE) - Medellin, Colombia (2019.12.4-2019.12.6)] 2019 FISE-IEEE/CIGRE Conference - Living the energy Transition (FISE/CIGRE) - Abating carbon emissions by means of utility-scale photovoltaics and storage: the Duke Energy Progress/Carolinas case study
摘要： A Sn-doped (100) β-Ga2O3 epitaxial layer was grown via metal–organic vapor phase epitaxy onto a single-crystal, Mg-doped semi-insulating (100) β-Ga2O3 substrate. Ga2O3-based metal–oxide–semiconductor field-effect transistors with a 2-μm gate length (L G), 3.4-μm source–drain spacing (LSD), and 0.6-μm gate–drain spacing (LGD) were fabricated and characterized. Devices were observed to hold a gate-to-drain voltage of 230 V in the OFF-state. The gate-to-drain electric field corresponds to 3.8 MV/cm, which is the highest reported for any transistor and surpassing bulk GaN and SiC theoretical limits. Further performance projections are made based on layout, process, and material optimizations to be considered in future iterations.
关键词： MOVPE,β-Ga2O3,MOSFETs,power semiconductor devices
更新于2025-09-23 15:19:57
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A review of <i>β</i> -Ga <sub/>2</sub> O <sub/>3</sub> single crystal defects, their effects on device performance and their formation mechanism
摘要： As a wide-bandgap semiconductor (WBG), β-Ga2O3 is expected to be applied to power electronics and solar blind UV photodetectors. In this review, defects in β-Ga2O3 single crystals were summarized, including dislocations, voids, twin, and small defects. Their effects on device performance were discussed. Dislocations and their surrounding regions can act as paths for the leakage current of SBD in single crystals. However, not all voids lead to leakage current. There’s no strong evidence yet to show small defects affect the electrical properties. Doping impurity was definitely irrelated to the leakage current. Finally, the formation mechanism of the defects was analyzed. Most small defects were induced by mechanical damages. The screw dislocation originated from a subgrain boundary. The edge dislocation lying on a plane slightly tilted towards the (102) plane, the (101) being the possible slip plane. The voids defects like hollow nanopipes, PNPs, NSGs and line-shaped grooves may be caused by the condensation of excess oxygen vacancies, penetration of tiny bubbles or local meltback. The nucleation of twin lamellae occurred at the initial stage of “shoulder part” during the crystal growth. These results are helpful in controlling the occurrence of crystal defects and improving the device performance.
关键词： formation mechanism,crystal defects,β-Ga2O3,device performance
更新于2025-09-19 17:15:36
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Progress of power field effect transistor based on ultra-wide bandgap Ga <sub/>2</sub> O <sub/>3</sub> semiconductor material
摘要： As a promising ultra-wide bandgap semiconductor, gallium oxide (Ga2O3) has attracted increasing attention in recent years. The high theoretical breakdown electrical field (8 MV/cm), ultra-wide bandgap (~ 4.8 eV) and large Baliga’s figure of merit (BFOM) of Ga2O3 make it a potential candidate material for next generation high-power electronics, including diode and field effect transistor (FET). In this paper, we introduce the basic physical properties of Ga2O3 single crystal, and review the recent research process of Ga2O3 based field effect transistors. Furthermore, various structures of FETs have been summarized and compared, and the potential of Ga2O3 is preliminary revealed. Finally, the prospect of the Ga2O3 based FET for power electronics application is analyzed.
关键词： ultra-wide bandgap semiconductor,field effect transistor (FET),power device,gallium oxide (Ga2O3)
更新于2025-09-19 17:15:36
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Source-field-plated Ga <sub/>2</sub> O <sub/>3</sub> MOSFET with a breakdown voltage of 550 V
摘要： Ga2O3 metal–oxide–semiconductor field-effect transistors (MOSFETs) with high-breakdown characteristics were fabricated on a homoepitaxial n-typed β-Ga2O3 film, which was grown by metal organic chemical vapor deposition (MOCVD) on an Fe-doped semi-insulating (010) Ga2O3 substrate. The structure consisted of a 400 nm unintentionally doped (UID) Ga2O3 buffer layer and an 80 nm Si-doped channel layer. A high k HfO2 gate dielectric film formed by atomic layer deposition was employed to reduce the gate leakage. Moreover, a source-connected field plate was introduced to enhance the breakdown characteristics. The drain saturation current density of the fabricated device reached 101 mA/mm at Vgs of 3 V. The off-state current was as low as 7.1 × 10?11 A/mm, and the drain current ION/IOFF ratio reached 109. The transistors exhibited three-terminal off-state breakdown voltages of 450 and 550 V, corresponding to gate-to-drain spacing of 4 and 8 μm, respectively.
关键词： MOSFET,Ga2O3,filed plate,breakdown voltage
更新于2025-09-19 17:15:36
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Flexible β-Ga <sub/>2</sub> O <sub/>3</sub> Nanomembrane Schottky Barrier Diodes
摘要： Here, high power flexible Schottky barrier diodes (SBDs) are demonstrated on a plastic substrate using single crystalline β-Ga2O3 nanomembranes (NMs). In order to realize flexible high power β-Ga2O3 SBDs, sub-micron thick freestanding β-Ga2O3 NMs are created from a bulk β-Ga2O3 substrate and transfer-printed onto the plastic substrate via a microtransfer printing method. It is revealed that the material property of β-Ga2O3 NMs such as crystal structure, electron affinity, and bandgap remains unchanged compared with its bulk properties. Flexible β-Ga2O3 SBDs exhibit the record high critical breakdown field strength (Ec) of 1.2 MV cm?1 in the flat condition and 1.07 MV cm?1 of Ec under the bending condition. Overall, flexible β-Ga2O3 SBDs offer great promise for future flexible energy convergence systems and are expected to provide a much larger and more versatile platform to address a broader range of high-performance flexible applications.
关键词： flexible Schottky barrier diodes,high power flexible electronics,β-Ga2O3 nanomembrane
更新于2025-09-19 17:15:36
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Metal-Semiconductor-Metal ?μ-Ga2O3 Solar-Blind Photodetectors with a Record High Responsivity Rejection Ratio and Their Gain Mechanism
摘要： In recent years, Ga2O3 solar-blind photodetector (SBPD) has been attached great attention for its potential application in solar-blind imaging, deep space exploration, and confidential space communication, etc. In this work, we demonstrated an ultrahigh performance ε-Ga2O3 metal-semiconductor-metal (MSM) SBPD. The fabricated photodetectors exhibited record-high responsivity and fast decay time of 230 A/W and 24 ms, respectively, compared with MSM-structured Ga2O3 photodetectors reported to date. Additionally, the ε-Ga2O3 MSM SBPD presents ultrahigh detectivity of 1.2×1015 Jones with low dark current of 23.5 pA under the operation voltage of 6 V, suggesting its strong capability of detecting an ultraweak signal. The high sensitivity and wavelength selectivity of the photodetector were further confirmed by the record high responsivity rejection ratio (R250nm/R400nm) of 1.2×105. From the temperature-dependent electrical characteristics in the dark, the thermionic field emission and Poole-Frenkel emission were found to be responsible for the current transport in the low and high electric field regimes, respectively. In addition, the gain mechanism was revealed by the Schottky barrier lowering effect due to the defect states at the interface of metal contact and Ga2O3 or in the bulk of Ga2O3 based on current transport mechanism and density functional theory (DFT) calculation. These results facilitate a better understanding of ε-Ga2O3 photoelectronic devices and provide possible guidance for promoting their performance in future solar-blind detection applications.
关键词： rejection ratio,metal-organic chemical vapor deposition,ε-Ga2O3,responsivity,high-performance,solar-blind photodetector
更新于2025-09-19 17:13:59
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Flexible solar blind Ga2O3 ultraviolet photodetectors with high responsivity and photo-to-dark current ratio
摘要： In this work, flexible solar blind Ga2O3 ultraviolet photodetectors with high responsivity and photo-to-dark current ratio are demonstrated. The Ga2O3 films are obtained by the RF magnetron sputtering method on flexible polyimide (PI) substrates and the results demonstrate that all the films grown under various temperatures are amorphous. When the incident light wavelength is less than 254 nm, the incident light is effectively absorbed by the Ga2O3 film. By controlling the growth temperature of the material, the responsivity and photo-to-dark current ratio of the corresponding metal-semiconductor-metal photodetectors are significantly improved. At growth temperature of 200 oC, the current under 254 nm illumination obtains 396 nA at voltage of 20 V (corresponding responsivity is 52.6 A/W), the photo-to-dark current ratio is more than 105, and the external quantum efficiency reaches 2.6×10 4 %, which is among the best reported Ga2O3 ultraviolet photodetectors including the devices on the rigid substrates. After the bending and fatigue tests, the flexible detectors have negligible performance degradation, showing excellent mechanical and electrical stability.
关键词： solar blind photodetector,responsivity,photo-to-dark current ratio,Ga2O3,flexible device
更新于2025-09-19 17:13:59
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High Responsivity and High Rejection Ratio Self-Powered Solar-Blind Ultraviolet Photodetector Based on PEDOT:PSS/β-Ga2O3 Organic/Inorganic p-n Junction
摘要： A high responsivity self-powered solar-blind deep UV (DUV) photodetector with high rejection ratio was proposed based on inorganic/organic hybrid p-n junction. Owing to the high crystalized β-Ga2O3 and excellent transparent conductive polymer PEDOT:PSS, the device exhibited ultrahigh responsivity of 2.6 A/W at 245 nm with a sharp cut off wavelength at 255 nm without any power supply. The responsivity is much larger than that of previous solar-blind DUV photodetectors. Moreover, the device exhibited an ultrahigh solar-blind/UV rejection ratio (R245 nm /R280 nm) of 103, which is two orders of magnitude larger than the average value ever reported in Ga2O3-based solar-blind photodetectors. In addition, the photodetector shows a narrow band-pass response of only 17 nm in width. This work might be of great value in developing high wavelength selective DUV photodetector with respect to low cost for future energy-efficient photoelectric devices.
关键词： Self-Powered,PEDOT:PSS/β-Ga2O3,Plasmonics and Optoelectronics,Organic/Inorganic p-n Junction,Energy Conversion and Storage,High Rejection Ratio,High Responsivity,Solar-Blind Ultraviolet Photodetector
更新于2025-09-19 17:13:59