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Ga2O3-based photodetectors are promising for deep ultraviolet (DUV) detection owing to the relatively large bandgap (>4.5 eV) of Ga2O3. High-temperature applications, such as flame detection and aerospace have been a major challenge to the reliability of electronic devices including photodetectors. All-oxide electronic devices have great potential for applications that require high thermal stability. Therefore, we constructed an all-oxide self-powered DUV photodetector based on ϵ -Ga2O3/ZnO heterojunction and examined its ruggedness in a high-temperature environment up to 600 K. A photocurrent of up to 0.3 μ A and a photo-to-dark current ratio of ∼8000 were observed at room temperature. In addition, the ϵ -Ga2O3/ZnO heterojunction remained functional even at an ambient temperature of 600 K. It was also found that sensing performance including photo-to-dark current ratio (PDCR), responsivity, detectivity, and external quantum efficiency degraded as the temperature increased. Detailed generation/recombination processes, as well as carrier transport, were explored to reveal physical insights. The thermal stability of the ϵ -Ga2O3/ZnO photodetector is thus examined, which would provide the basis for further development. [ABSTRACT FROM AUTHOR]

• BiOCl/Bi 4 NbO 8 Cl heterostructures were in situ formed by one-step acid-etching. • Impurities accompanied by Bi 4 NbO 8 Cl were removed by glacial acetic acid. • BiOCl/Bi 4 NbO 8 Cl photocatalysts owned superior performance in degrading CIP/RhB. • Heterojunctions promote charge separation in the composites. In this study, BiOCl/Bi 4 NbO 8 Cl heterojunctions with improved photocatalytic performance were designed and synthesized by in-situ room-temperature acid-etching. Bi 4 NbO 8 Cl prepared by the solid-phase method was often accompanied by certain impurities, such as Bi 24 O 31 Cl 10 and Bi 3 NbO 7. With the assistance of glacial acetic acid, the impurities could be eliminated. At the same time, BiOCl nanosheets were formed in situ at room temperature, and BiOCl/Bi 4 NbO 8 Cl (BBN) heterostructures were obtained. For comparison, pure Bi 4 NbO 8 Cl was prepared using the molten salt method (S-BNC). Compared to S-BNC, BBN exhibited better performance in degrading rhodamine B (RhB) and ciprofloxacin (CIP). The mechanism of the improved photocatalytic activities was studied by analyzing photoluminescence spectra, UV–vis diffuse reflection absorption spectra, and cyclic voltammetry curves. Acid-etching assisted synthesis of BiOCl/Bi 4 NbO 8 Cl heterostructures via in-situ strategy enhance the purity of the composite and charge transfer at the interface. [Display omitted] [ABSTRACT FROM AUTHOR]

Heterojunction photodetectors (PDs) with photovoltaic effect could play a crucial role in future energy-conservation photoelectronic devices for their self-powered work manner. Herein, a self-powered PD was successfully constructed on the all-oxide Ga2O3/V2O5 thin-film heterojunction. With a type-I straddling band alignment, the Ga2O3/V2O5 heterostructure demonstrated an obvious photovoltaic effect with an open-circuit voltage of 0.4 V. The large bandgap (5.01 eV) of $\beta $ -Ga2O3 and the effective electron–hole pair separation within heterointerface produced a superhigh solar-blind spectral discriminability for the Ga2O3/V2O5 heterojunction PD, with deep-ultraviolet (DUV)/visible rejection ratio (${R}_{{240}}/{R}_{{400}}$) of 6.0 $\times 10^{{4}}$ , photo-to-dark current ratio (PDCR) of $2.6 \times 10^{{7}}$ , on/off switching ratio of $1.87\times 10^{{5}}$ , and specific detectivity of 7.8 $\times 10^{{13}}$ Jones. The largest responsivities in self-powered mode (0 V) and power-supply mode (−5 V) were 19.8 and 79.2 mA/W, respectively. The excellent self-powered photodetection performance of Ga2O3/V2O5 oxide heterojunction provides a new strategy for next-generation energy-conservation solar-blind PDs. [ABSTRACT FROM AUTHOR]

• A β-Ga 2 O 3 /CuBiI 4 heterojunction deep-ultraviolet photodetector was constructed. • The fabricated device exhibited responsivity of 20.68 A/W and detectivity of 3.72 × 1015 Jones. • The detector could display self-powered operation. Herein, a β-Ga 2 O 3 /CuBiI 4 heterojunction deep-ultraviolet (DUV) photodetector was constructed based on metal-organic chemical vapor deposition grown β-Ga 2 O 3 film and spin-coated CuBiI 4 film. In which, we prepared the pure and well-crystallized CuBiI 4 film from environment-friendly materials under optimized experimental conditions. The fabricated device exhibited a large responsivity of 20.68 A/W, a high specific detectivity of 3.72 × 1015 Jones, a high photo-to-dark current ratio of 5.62 × 106, a low dark current of 0.385 pA, and an ultrahigh UV/visible rejection ratio (R 250 nm / R 400 nm) of 1.14 × 104 under 254 nm UV light illumination at 5 V. In all, the device can sensitively monitor a wide range of UV light (254 nm) intensities from 0.1 to 2000 μW/cm2. Moreover, the potential of the device operating under self-powered mode has been verified, and the intrinsic physical mechanism of the heterojunction photodetector was analyzed via energy-band alignment. Overall, this work would present a promising route to realize high-performance and cost-effective DUV photodetector. [ABSTRACT FROM AUTHOR]

• Solution processed VOx films obtain changeable conductivities in 2 orders of magnitude range. • Regulable conductivity of VO x enables effective hole-transport engineering in VO x /Ga 2 O 3 heterojunction. • Optimized VO x /Ga 2 O 3 photodetector demonstrates enhanced self-powered ultraviolet photodetection performance. The self-powered photodetection performance of the VO x /Ga 2 O 3 heterojunction photodetector could be effectively and positively regulated via the VO x hole transport layer by charge-carrier engineering, inducing the record PDCR of 1.08 × 108 and superhigh on/off ratio of 1.23 × 106. [Display omitted] As the carrier behavior is crucial to the photoelectric conversion process, the charge-carrier engineering could provide feasible strategy for high-performance photodetector (PD). Herein, self-powered ultraviolet PDs were constructed on VO x /Ga 2 O 3 (VGO) heterojunctions by adopting the solution processed VO x films as hole transport layer (HTL). Treated with different annealing ambients, the HTL demonstrated changeable conductivities due to the regulated crystallinities, phase structures and chemical valences, which further exerted influences on the VGO PDs inducing controllable photodetection properties. With effective hole transportation, low valence band barrier and large built-in field, the modulated VGO PDs achieved enhanced self-powered photodetection performance with photo-to-dark current ratio of 1.08 × 108, on/off ratio of 1.23 × 106, rejection ration (R 245 / R 400) of 3.12 × 104, responsivity of 28.9 mA/W and detectivity of 1.13 × 1014 Jones as well as rise/decay time of 57/74 ms. In consideration of the carrier-transport problems are commonly ubiquitous and particularly vital, our proposed HTL engineering method could open the high-performance route for self-powered ultraviolet PDs. [ABSTRACT FROM AUTHOR]

Herein, a CuSCN/Ga 2 O 3 heterojunction device was fabricated by spin-coating and metal-organic chemical vapor deposition (MOCVD) methods. Under the irradiation of 254 nm deep ultraviolet (DUV) light with an intensity of 1000 μ W/cm 2 , the device shown high sensitivity and favorable self-powered performances with photo-to-dark current ratio (PDCR) of 1.29 × 10 4 , photo responsivity (R) of 5.5 mA/W, rejection ratio (R 270nm / R 600nm) of 4.33 × 10 3 , and specific detectivity (D ∗) of 3.8 × 10 11 cm Hz 1/2 W − 1 (Jones) at − 5 V. In addition, the device has a rise time of 0.45 s and 3.80 s, and a decay time of 0.26 s and 0.26 s. In general, the CuSCN/Ga 2 O 3 heterojunction prepared in this work may well be a potential candidate for achieving a self-powered and high-performance DUV photodetector. • A p-CuSCN/n-Ga 2 O 3 thin film heterojunction is constructed for performing DUV detection. • Under the irradiation of 254 nm DUV light with an intensity of 1000 μ W/cm2, at bias of -5 V, the device shown good performances. • The heterojunction photodetector could operate at zero bias. [ABSTRACT FROM AUTHOR]