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- 实验方案
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AlGaN Solar-Blind Avalanche Photodiodes with p-Type Hexagonal Boron Nitride
摘要： To improve the performances of AlGaN solar-blind avalanche photodiodes (APD), we propose a separate absorption and multiplication AlGaN APD with a p-hBN layer. The simulated results show that the p-hBN/AlGaN APD significantly decreases the breakdown voltage almost by 23% in comparison with the conventional AlGaN APD due to the use of p-hBN which has a wider bandgap, a higher p-type doping efficiency, and a smaller spontaneous polarization. Moreover, the designed APD keeps an intrinsic solar-blind characteristic even at large reverse bias because the h-BN is completely transparent in the long wavelength direction outside the solar-blind region. The result also confirms that the p-hBN/AlGaN APD has the lower Flicker and impact ionization noise at low and medium frequency under breakdown voltage.
关键词： h-BN,solar-blind,avalanche photodiodes,AlGaN
更新于2025-09-23 15:21:21
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Ultra-wide-bandgap (ScGa)2O3 alloy thin films and related sensitive and fast responding solar-blind photodetectors
摘要： Although b-Ga2O3 is considered an excellent candidate for solar-blind photodetectors (PDs) owing to its direct bandgap (4.9 eV) and high stability, the cut-off wavelength often oversteps the DUV region, reducing the rejection ratio of the PD. Moreover, oxygen vacancies, which always appear in b-Ga2O3 ?lms, act as trap centers hindering carrier recombination and signi?cantly lowering response speed. To disentangle these issues, we propose in this work to modify b-Ga2O3 by incorporating Sc to form ternary (ScGa)2O3 alloys. Thanks to the wider bandgap of Sc2O3 (~5.7 eV) than Ga2O3 and stronger SceO bonding than GaeO, the (ScGa)2O3 alloy ?lms exhibit a wider bandgap (5.17 eV) with fewer oxygen vacancies compared with pure-Ga2O3, as expected, which eventually lead to an ultra-low dark current (0.08 pA at 10 V) and faster response times (trise: 41/149 ms; tdecay: 22/153 ms) of the alloy ?lm-based PDs. Furthermore, the peak and cut-off response wavelengths of the (ScGa)2O3 PD are blue shifted relative to the pure Ga2O3 PD, resulting in a higher rejection ratio (>500 vs ~317). The Sc-alloying strategy, taking advantage of wider bandgap of Sc2O3 and stronger SceO bonding to widen the bandgap while reducing the intrinsic carriers and oxygen vacancies in the (ScGa)2O3 alloy, is expected to be generally applicable to the design of other wide-bandgap oxide alloys for developing high-performance UV photodetectors with a low dark current and high response speed.
关键词： Ga2O3 thin ?lms,Pulsed laser deposition,Solar-blind photodetectors,Sc-alloying
更新于2025-09-23 15:21:01
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High-performance amorphous BeZnO-alloy-based solar-blind ultraviolet photodetectors on rigid and flexible substrates
摘要： In this study, the bandgap of ternary alloy BeZnO was modulated to make the material applicable to solar-blind ultraviolet (UV) radiation detection. This was done by preparing amorphous films with high Be doping contents on rigid c-sapphire and flexible polyethylene terephthalate (PET) and polyethylene naphthalene (PEN) substrates. After depositing a pair of parallel Al electrodes, amorphous BeZnO-alloy-based solar-blind UV photodetectors (PDs) with peak responsivity occurring at around 230 nm were constructed and their cut-off wavelengths are less than 284 nm. The PDs constructed on three substrates exhibit extremely low dark currents of 58.7 pA, 2.9 pA, and 1.8 pA, respectively. Time-dependent photoresponse cycling confirmed devices reproducible, and sensitive to solar-blind UV radiation. More importantly, the devices exhibited fast response speeds with rise times of approximately 40 ms and particularly fast recovery speeds with decay times of approximately 10 ms. Our research provides a method of constructing high-performance PDs on various substrates. And constructing amorphous solar-blind UV PDs on flexible substrate in this work is expected to be guiding significance to the design of PDs with deformability.
关键词： Amorphous BeZnO alloy,Fast recovery speed,Solar blind photodetectors,Flexible substrate,High Be content
更新于2025-09-23 15:21:01
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Fabrication and characterization of Mg-doped ?μ-Ga2O3 solar-blind photodetector
摘要： In this work, Mg-doped ε-Ga2O3 (3.38 cation % of Mg) solar-blind photodetector is fabricated by using radio-frequency magnetron sputtering and metal-organic chemical vapor deposition methods on sapphire substrate. The results show that the Mg-doped ε-Ga2O3 thin film solar-blind photodetector exhibit a photo-to-dark current ratio of 1.68 102, responsivity of 77.2 mA/W, specific detectivity of 2.85 1012 Jones, and external quantum efficiency of 37.8 % at 5 V under 40 μW/cm2 254 nm ultraviolet light illumination, as well as the stable light switching property driven by different applied voltages and light intensities. The achieved Mg-doped ε-Ga2O3 solar-blind photodetector is promised to advance relevant developments of the metastable Ga2O3 optoelectronic devices.
关键词： MOCVD,solar-blind,Mg dopant,magnetron sputtering,ε-Ga2O3
更新于2025-09-23 15:21:01
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Thermo-environomic assessment of an integrated greenhouse with an adjustable solar photovoltaic blind system
摘要： Optimum energy consumption and renewable energy utilization reduce environmental impacts and are cost-effective. They are the key aspects of achieving sustainable energy management, such as in the agricultural industry. The contribution of the horticultural section in the global energy demand is approximately 2%, and among its various sections, greenhouses are one of the main systems in modern agriculture that have a great share on energy consumption. In this study, a rose greenhouse is examined and modeled in EnergyPlus as a greenhouse reference (GR). Validation of the developed greenhouse model is carried out with a site experimental measurement. Using the GR as the basic model, 14 various configurations of greenhouses have been assessed by considering a solar photovoltaic blind system (SPBS) in checkerboard arrays 1 meter above the greenhouse roof. These modified greenhouses called solar-blind greenhouses (SBGs) have different shading rates and SPBS sizes. To perform a Thermo-environomic assessment, the effects of various parameters, including temperature, relative humidity, natural gas consumption, electricity consumption, and carbon dioxide (CO2) emission reduction, are studied. Results indicate that covering 19.2% of the roof, with no significant change in the illumination level on the plant canopy, will annually reduce natural gas consumption, electricity demand, and CO2 emission by 3.57%, 45.5%, and 30.56 kg/m2, respectively. Moreover, with the SPBS, the annual electricity production is approximated at 42.7 kWh/m2.
关键词： Energy,Solar Greenhouse,Photovoltaic,Thermo-environomic,Solar Blind System
更新于2025-09-23 15:19:57
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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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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-speed colour-converting photodetector with all-inorganic CsPbBr3 perovskite nanocrystals for ultraviolet light communication
摘要： Optical wireless communication (OWC) using the ultra-broad spectrum of the visible-to-ultraviolet (UV) wavelength region remains a vital field of research for mitigating the saturated bandwidth of radio-frequency (RF) communication. However, the lack of an efficient UV photodetection methodology hinders the development of UV-based communication. The key technological impediment is related to the low UV-photon absorption in existing silicon photodetectors, which offer low-cost and mature platforms. To address this technology gap, we report a hybrid Si-based photodetection scheme by incorporating CsPbBr3 perovskite nanocrystals (NCs) with a high photoluminescence quantum yield (PLQY) and a fast photoluminescence (PL) decay time as a UV-to-visible colour-converting layer for high-speed solar-blind UV communication. The facile formation of drop-cast CsPbBr3 perovskite NCs leads to a high PLQY of up to ~73% and strong absorption in the UV region. With the addition of the NC layer, a nearly threefold improvement in the responsivity and an increase of ~25% in the external quantum efficiency (EQE) of the solar-blind region compared to a commercial silicon-based photodetector were observed. Moreover, time-resolved photoluminescence measurements demonstrated a decay time of 4.5 ns under a 372-nm UV excitation source, thus elucidating the potential of this layer as a fast colour-converting layer. A high data rate of up to 34 Mbps in solar-blind communication was achieved using the hybrid CsPbBr3–silicon photodetection scheme in conjunction with a 278-nm UVC light-emitting diode (LED). These findings demonstrate the feasibility of an integrated high-speed photoreceiver design of a composition-tuneable perovskite-based phosphor and a low-cost silicon-based photodetector for UV communication.
关键词： CsPbBr3 perovskite nanocrystals,Silicon-based photodetector,UV photodetection,Solar-blind UV communication,Optical wireless communication
更新于2025-09-19 17:13:59