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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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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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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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Photoelectrochemical Self-Powered Solar-Blind Photodetectors Based on Ga2O3 Nanorod Array/Electrolyte Solid/Liquid Heterojunctions with a Large Seperation Interface of Photogenerated Carriers
摘要： Solar-blind photodetectors have been widely developed because of their great potential application in biological analysis, ultraviolet communication, and so on. Photodetectors constructed by vertically aligned nanorod arrays (NRAs), have attracted intensive interest recently owing to the virtues of low light reflectivity and rapid electron transport. However, limited by the insufficient contact between the upper electrode and NRAs because of uneven NRAs, photo-generated carriers cannot be effectively separated and transferred. In this work, a novel photoelectrochemical (PEC) type self-powered solar-blind photodetectors constructed in the form of Ga2O3 NRAs/electrolyte solid/liquid heterojunction with a large photogenerated carrier separation interface has been fabricated, β-Ga2O3 NRAs PEC photodetector shows a photoresponsivity of 3.81 mA/W at a bias voltage of 0 V under the 254 nm light illumination with the light intensity of 2.8 mW/cm2, thus yielding a Iphoto/Idark ratio of 28.97 and an external quantum efficiency of 1.86 %. Our results provide a novel device structure of solar-blind photodetector with high efficient deep-ultraviolet photodetection and low power consumption.
关键词： photoelectrochemical,Ga2O3 NRAs,solid-liquid heterojunction,solar-blind photodetectors,self-powered
更新于2025-09-11 14:15:04
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Wearable Gallium Oxide Solar-blind Photodetectors on Muscovite Mica Having Ultra-High Photoresponsivity And Detectivity With Added High Temperature Functionalities
摘要： Wearable Gallium oxide solar-blind photodetector fabricated on muscovite mica is reported for room temperature as well as high temperature operations. The ultra-high photoresponsivity of 9.7 A/W is obtained for 5V applied bias at room temperature under 75 μW/cm2 weak illumination of 270 nm wavelength. The detector enables very low noise equivalent power (NEP) of 9×10-13 W/Hz1/2 and ultra-high detectivity of 2×1012 jones which shows the magnificent detection sensitivity. Further, bending tests are performed for robust utilization of flexible detectors up to 500 bending cycles with each bending radius of 5 mm. After 500 bending cycles, device shows slight photocurrent decrease. The bending performances exhibit excellent potential for wearable applications. Moreover, photocurrent and dark current characteristics above room temperature demonstrate the outstanding functionalities till 523K temperature which is remarkable for flexible photodetectors. The obtained results show the potential of Gallium oxide solar-blind photodetectors at room temperature and high temperatures environments which pave the ways for futuristic smart and flexible sensors.
关键词： photoresponse,Gallium Oxide,Solar-blind photodetectors,detectivity,flexible photodetector,Mica
更新于2025-09-11 14:15:04
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Gallium Oxide || Ga2O3 nanobelt devices
摘要： β-Gallium oxide (β-Ga2O3) is attractive as a novel material for (opto)electronics, especially high-power electronics and solar-blind photodetectors (PDs). It has an ultrawide direct bandgap of around 4.8–4.9 eV at room temperature and high thermal and chemical stabilities [1, 2]. The theoretical electrical breakdown field (Ebr) of β-Ga2O3 is known to be (cid:1)8 MV/cm, and 3.8 MV/cm of Ebr has been experimentally demonstrated in a recent report, recording a higher value than those of GaN and SiC. Baliga’s figure of merit (BFOM) of β-Ga2O3 is also superior among some of the other popular wide-bandgap semiconductors, such as 4H-SiC and GaN [3–6]. These outstanding properties have led to a large number of reports on various electrical devices based on β-Ga2O3 including metal-oxide-semiconductor field-effect transistors (MOSFETs), metal-semiconductor field-effect transistors (MESFETs), and Schottky barrier diodes [7–10]. Furthermore, the wide bandgap of β-Ga2O3 provides intrinsic solar blindness that allows fabrication of solar-blind PDs without the need for additional optical filters that block light in the range of long wavelength [11]. Single-crystal β-Ga2O3 is commercially available as a various of growth methods exist; especially the edge-defined film-fed growth (EFG) method that can be used to grow bulk β-Ga2O3 substrates with high crystal quality [12, 13]. However, the low thermal conductivity of β-Ga2O3 has to be considered when fabricating high-power electrical devices.
关键词： high-power electronics,β-Ga2O3,wide-bandgap semiconductors,optoelectronics,solar-blind photodetectors
更新于2025-09-09 09:28:46