- 标题
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- 实验方案
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Fabrication of ?μ-Ga<sub>2</sub>O<sub>3</sub> solar-blind photodetector with symmetric interdigital Schottky contacts responding to low intensity light signal
摘要： Owing to the constraint of carrier transport, the dark current is relatively lower in Schottky contacted devices than that in Ohmic contacted devices, leading to a high specific detectivity in photodetectors. In this work, we prepared ε-Ga2O3 thin film by using metal-organic chemical vapor deposition, then constructed a three-pair interdigital ultraviolet solar-blind photodetector with Au electrodes as Schottky contacts. Seen from the results, this photodetector displays an outstanding wavelength selectivity with responsivity of 0.52 A W-1 responding to 250 nm wavelength light. In addition, it shows a photo-to-dark current ratio of 1.82 × 104/6.03 × 102 at 5 V under 40/5 μW cm-2 254 nm light illuminations, respectively, and a low dark current of 1.87 × 10-11 A. Correspondingly, the specific detectivity is 1.67 × 1012 Jones, and the photoresponsivity is 0.198 A W-1/52.54 mA W-1. Overall, ε-Ga2O3 prepared here is certified to be an excellent candidate material to perform high-performance solar-blind detection.
关键词： ε-Ga2O3,high detectivity,Schottky contact,solar-blind photodetector
更新于2025-09-19 17:13:59
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Dual‐Channel Solar‐Blind UV Photodetector Based on β‐Ga <sub/>2</sub> O <sub/>3</sub>
摘要： The photoconductivity (PC) of β-Ga2O3 single crystals is investigated. A complex PC band is detected in the UV region of 230–270 nm. The PC spectra recorded in polarized light are different for the E∥band E⊥borientations of the electric vector of light wave Ewith respect to the baxis of the β-Ga2O3 crystal. Anisotropy of PC is utilized to create a dual-channel UV photodetector with maximum channel sensitivity centered at 245 and 262 nm, for the E∥b and E⊥b orientations, respectively. The sensitivity and some other parameters of the UV photodetector are estimated.
关键词： anisotropies,β-Ga2O3 single crystals,UV photodetectors,photoconductivities
更新于2025-09-19 17:13:59
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Crystal Growth and Structure-Property Optimization of Thermally Annealed Nanocrystalline Ga2O3 Films
摘要： The effects of thermal annealing on the crystal chemistry, crystallization process, index of refraction, mechanical properties, and electrical characteristics of nanocrystalline Ga2O3 films was evaluated. Ga2O3 thin films were sputtered onto Si(100) substrates at 500 oC utilizing a Ga2O3 ceramic target, while post-deposition thermal annealing was performed between a range of 500-900 oC. Both structural quality and packing density of the Ga2O3 films was improved by the thermal annealing as indicated by the X-ray diffraction and ellipsometry studies. The atomic force microscopy analysis indicates that the annealing temperature has a dramatic effect on surface roughness, especially when the annealing temperature exceeds 700 oC. Corroborating with structure and morphology changes, the high values of hardness and elastic modulus are noted for Ga2O3 films annealed at higher temperatures (800-900 oC). Index of refraction (n) and extinction coefficient (k) results, and their dispersion profiles indicate that the annealing temperature strongly influences the optical properties. The refractive index values vary in the range of 1.78–1.84 (632 nm) due to gradual improvement of structural quality, texturing and packing density upon thermal annealing. A correlation between annealing temperature, optical and electrical characteristics in Ga2O3 films is established.
关键词： Mechanical Properties,Sputter-deposition,Annealing,Electrical Properties,β-Ga2O3 Films,Crystal Chemistry
更新于2025-09-19 17:13:59
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Tailoring the solar-blind photoresponse characteristics of ?2-Ga2O3 epitaxial films through lattice mismatch and crystal orientation
摘要： Realizing manipulation of the photoelectric properties of wide bandgap semiconductors is a main challenge for succeeding next-generation functional optoelectronics. As an intriguing wide bandgap semiconductor, β-Ga2O3 (Eg ~ 4.9 eV) is emerging as a promising candidate for photodetectors operating in solar-blind region. Here, we show that by selecting substrates with different symmetries and lattice parameters [i.e. (100) MgO, (100) MgAl2O4 and (0001) α-Al2O3], epitaxial β-Ga2O3 films with (100)- or (2?01)-oriented could be fabricated. We found that the photoresponse characteristics are strongly correlated with the lattice mismatch and film orientation. In particular, (100)-oriented β-Ga2O3 film grown on MgO substrate with smaller lattice mismatch exhibited a 254 nm responsivity of 0.1 A·W-1 and detectivity of 4.3×1012 Jones, which are approximately an order of magnitude higher than that of the (2?01)-oriented β-Ga2O3 film. Our work may provide a strategy to develop further high performance solar-blind photodetectors.
关键词： β-Ga2O3,crystal orientation,epitaxial films,lattice mismatch,solar-blind photodetectors
更新于2025-09-19 17:13:59
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Perspective: Ga <sub/>2</sub> O <sub/>3</sub> for ultra-high power rectifiers and MOSFETS
摘要： Gallium oxide (Ga2O3) is emerging as a viable candidate for certain classes of power electronics with capabilities beyond existing technologies due to its large bandgap, controllable doping, and the availability of large diameter, relatively inexpensive substrates. These applications include power conditioning systems, including pulsed power for avionics and electric ships, solid-state drivers for heavy electric motors, and advanced power management and control electronics. Wide bandgap (WBG) power devices offer potential savings in both energy and cost. However, converters powered by WBG devices require innovation at all levels, entailing changes to system design, circuit architecture, qualification metrics, and even market models. The performance of high voltage rectifiers and enhancement-mode metal-oxide field effect transistors benefits from the larger critical electric field of β-Ga2O3 relative to either SiC or GaN. Reverse breakdown voltages of over 2 kV for β-Ga2O3 have been reported, either with or without edge termination and over 3 kV for a lateral field-plated Ga2O3 Schottky diode on sapphire. The metal-oxide-semiconductor field-effect transistors fabricated on Ga2O3 to date have predominantly been depletion (d-mode) devices, with a few demonstrations of enhancement (e-mode) operation. While these results are promising, what are the limitations of this technology and what needs to occur for it to play a role alongside the more mature SiC and GaN power device technologies? The low thermal conductivity might be mitigated by transferring devices to another substrate or thinning down the substrate and using a heatsink as well as top-side heat extraction. We give a perspective on the materials’ properties and physics of transport, thermal conduction, doping capabilities, and device design that summarizes the current limitations and future areas of development. A key requirement is continued interest from military electronics development agencies. The history of the power electronics device field has shown that new technologies appear roughly every 10-12 years, with a cycle of performance evolution and optimization. The older technologies, however, survive long into the marketplace, for various reasons. Ga2O3 may supplement SiC and GaN, but is not expected to replace them.
关键词： MOSFETs,β-Ga2O3,rectifiers,power electronics,thermal conductivity,Gallium oxide,Ga2O3,doping,wide bandgap semiconductors,military electronics
更新于2025-09-16 10:30:52
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Nanoplasmonic Enhanced High-performance Metastable Phase α-Ga2O3 Solar-blind Photodetector
摘要： In this work, nanoplasmonic enhanced α-Ga2O3 solar-blind photodetectors with interdigital structure were fabricated on sapphire. By introducing Al nanoparticles (NPs) onto the device surface, the photodetector obtained a significant increase in responsivity at solar-blind region, and the response peak located at 244 nm reached 3.36 A/W under applied voltage of 5 V. Compared with the responsivity at 320 nm, the response ratio exceeds 240, demonstrating a superior solar-blind cut-off edge. It also presents that the photocurrent was dramatically increased under the 254 nm ultraviolet irradiation for the enhanced device while the dark current remains below 1 pA at 20 V. To explicitly elucidate the enhancement effects by Al NPs under ultraviolet illumination, Kelvin probe force microscopy was employed and directly revealed the physical mechanism of surface plasmon oscillation which promoted the formation of localized electric fields on α-Ga2O3. In addition, we illustrated the effects of interdigital spacing on device performances through experimental measurements and theoretical calculations. These results not only provide direct evidences for Al nanoplasmonic enhancement on α-Ga2O3 device, but also facilitate design and fabrication of solar-blind photodetectors.
关键词： photodetector,nanoplasmonic,α-Ga2O3,solar-blind,interdigital
更新于2025-09-16 10:30:52
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Demonstration of low forward voltage InGaN-based red LEDs
摘要： Here we report InGaN-based red light-emitting diodes (LEDs) grown on (201) β-Ga2O3 substrates. AlN/AlGaN strain-compensating layers and hybrid multiple-quantum-well structures were employed to improve the crystalline-quality of the InGaN active region. A bare LED showed that peak wavelength, light output power, and external quantum efficiency were 665 nm, 0.07 mW, and 0.19% at 20 mA, respectively. As its forward voltage was 2.45 V at 20 mA, the wall-plug efficiency was 0.14%. The characteristic temperature of the LEDs was 222 K at 100 mA evaluated from the temperature dependence of electroluminescence.
关键词： InGaN,β-Ga2O3 substrates,red LEDs,multiple-quantum-well structures,strain-compensating layers
更新于2025-09-16 10:30:52
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Giant bulk photovoltaic effect in solar cell architectures with ultra-wide bandgap Ga2O3 transparent conducting electrodes
摘要： The use of ultra-wide bandgap transparent conducting beta gallium oxide (b-Ga2O3) thin films as electrodes in ferroelectric solar cells is reported. In a new material structure for energy applications, we report a solar cell structure (a light absorber sandwiched in between two electrodes - one of them - transparent) which is not constrained by the ShockleyeQueisser limit for open-circuit voltage (Voc) under typical indoor light. The solar blindness of the electrode enables a record-breaking bulk photovoltaic effect (BPE) with white light illumination (general use indoor light). This work opens up the perspective of ferroelectric photovoltaics which are not subject to the Shockley-Queisser limit by bringing into scene solar-blind conducting oxides.
关键词： Bulk photovoltaic effect,Pb(Zr,Ti)O3,Solar cell architecture,Ferroelectric photovoltaics,Ga2O3,Gallium oxide,Transparent conducting oxide,Ultra-wide bandgap semiconductors
更新于2025-09-16 10:30:52
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Phase-controlled epitaxial lateral overgrowth of ?±-Ga<sub>2</sub>O<sub>3</sub> by halide vapor phase epitaxy
摘要： We investigated the effect of mask materials on the epitaxial lateral overgrowth (ELO) characteristics of α-Ga2O3 and developed an ELO technique that can markedly suppress abnormal growth and cracking to enable long-term growth on a wide mask, which is necessary to effectively improve the crystal quality. A conventional SiOx mask provided excellent growth selectivity with only a thin amorphous GaOx layer on the mask between α-Ga2O3 islands. However, the amorphous layer transformed into β-Ga2O3, which disrupted the long-term growth of α-Ga2O3. Amorphous deposition was avoided by using a TiOx mask. When a TiOx mask was used, κ-Ga2O3 deposited on the mask, and no transformation to β-Ga2O3 was observed. α-Ga2O3 islands with a diameter as large as approximately 25 μm were grown by the developed ELO technique using a TiOx mask. Transmission electron microscopy observation did not detect dislocations in the outermost part of the islands.
关键词： crystal quality,α-Ga2O3,mask materials,halide vapor phase epitaxy,epitaxial lateral overgrowth
更新于2025-09-16 10:30:52
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The Growth of Ga2O3 Nanowires on Silicon for Ultraviolet Photodetector
摘要： We investigated the effect of silver catalysts to enhance the growth of Ga2O3 nanowires. The growth of Ga2O3 nanowires on a P+-Si (100) substrate was demonstrated by using a thermal oxidation technique at high temperatures (~1000 °C) in the presence of a thin silver film that serves as a catalyst layer. We present the results of morphological, compositional, and electrical characterization of the Ga2O3 nanowires, including the measurements on photoconductance and transient time. Our results show that highly oriented, dense and long Ga2O3 nanowires can be grown directly on the surface of silicon. The Ga2O3 nanowires, with their inherent n-type characteristics formed a pn heterojunction when grown on silicon. The heterojunction showed rectifying characteristics and excellent UV photoresponse.
关键词： electrical conductivity,nanowires,β-Ga2O3,oxidation,silver catalyst,photodetector
更新于2025-09-12 10:27:22