Pt/(InGa)₂O₃/n-Si Heterojunction-Based Solar-Blind Ultraviolet Photovoltaic Detectors with an Ideal Absorption Cutoff Edge of 280 nm

Abstract

Ga 2 O 3 is a popular material for research on solar-blind ultraviolet detectors. However, its absorption cutoff edge is 253 nm, which is not an ideal cutoff edge of 280 nm. In this work, by adjusting the ratio of In/Ga elements in the films, a high-quality (In 0.11 Ga 0.89 ) 2 O 3 film with an absorption cutoff edge of 280 nm was obtained, which owns a uniform surface and preferred orientation. On this basis, a solar-blind ultraviolet photovoltaic detector was constructed based on the Pt/(In 0.11 Ga 0.89 ) 2 O 3 /n-Si heterojunction. When the device is exposed to 254 nm UV light, its open-circuit voltage (V OC ) can reach 354 mV. Under 0 V bias, the device has a responsivity of 0.48 mA/W with a rise time of 0.47 s and a decay time of 0.37 s; under −7 V bias, the device achieves a responsivity of 16.96 mA/W with a rise time of 0.17 s and a decay time of 0.33 s. The spectral response characteristics of the device show that it has a selective response to solar-blind ultraviolet light (cutoff wavelength is 280 nm) with a rejection ratio (R 254 nm /R 310 nm ), which is greater by more than two orders of magnitude. This work provides a good reference for adjusting the band gap of Ga 2 O 3 -based films and broadening their application fields. KEYWORDS: photovoltaic photodetector, solar-blind ultraviolet, (In x Ga 1−x ) 2 O 3 , band gap adjustment, 280 nm

Narrow-Band Solar-Blind Ultraviolet Detectors Based on AlSnO Films with Tunable Band Gap

“…Figure 1d shows the transmittance spectra of the three films with various components, from which it can be seen that the cutoff wavelength of the films gradually decreases as the Al content increases. Figure 1e displays a plot of the band gap versus Al content; the band gaps of these films were estimated from the function between (αhν) 2 and hν. 26 It can be seen that there is a linear relationship between the band gap and component of AlSnO films, confirming that the band gap engineering of AlSnO in a wide range (3.93−5.43 eV) has been achieved.…”

“…Ultraviolet light with a wavelength of 200–280 nm from sunlight is absorbed by ozone within the atmosphere and cannot reach the ground, which is the origin of the term solar-blind ultraviolet (SBUV). , This characteristic makes it possible to utilize SBUV detecting equipment to accomplish the applications in need of SBUV detection, such as near-ground communication, , high-voltage corona discharge detection, flame detection, , and missile tracking …”

“…Ultraviolet light with a wavelength of 200−280 nm from sunlight is absorbed by ozone within the atmosphere and cannot reach the ground, which is the origin of the term solarblind ultraviolet (SBUV). 1,2 This characteristic makes it possible to utilize SBUV detecting equipment to accomplish the applications in need of SBUV detection, such as nearground communication, 3,4 high-voltage corona discharge detection, 5 flame detection, 6,7 and missile tracking. 8 Typically, wide-band-gap semiconductor materials with a band gap larger than 4.40 eV are always used to fabricate SBUV detectors, among which Ga 2 O 3 , 9 BN, 10,11 Si 3 N 4 , 12 and diamond 13 are representatives that offer the advantages of low operating voltage, improved reliability, and compact size.…”

Observation of Anomalous Negative Photoconductivity in Ga2O3 Nanowires: Implications for Broadening the Spectral Response of Photodetectors

“…Solar radiation with the spectral range from 200 to 280 nm cannot reach the earth’s surface because it is absorbed by ozone in the atmosphere, so it is called solar-blind light. − A wide bandgap semiconductor can be used as the material for solar-blind photodetectors because its absorption edge is falling within the range of solar-blind region, which is widely applied for ozone hole monitoring, fire detection, safety communication, and missile guidance system. ,− ZnO, Al x Ga 1– x N, BN, Zn x Mg 1– x O, Ga 2 O 3 , and diamond are the representatives of wide bandgap semiconductor materials, which have attracted tremendous attention in recent years. ,− Among them, Ga 2 O 3 has five phases (α, β, γ, δ, and ε). Nanostructured β-Ga 2 O 3 has the property of chemical and thermal stability, ,, with a direct bandgap (4.5–4.9 eV), ,, and the corresponding absorption edge just falls within the solar-blind range (200–280 nm), so it has been widely explored in recent years as a promising candidate for a solar-blind photodetector.…”

A Solar-Blind Ultraviolet Photodetector With Graphene/MgZnO/GaN Vertical Structure

“…Too low quality of the film may result in slow response speed, poor frequency response and low responsivity of the detector Li et al, 2019). In addition, the vertical structure of the heterojunction detector has better performance than the planar structure of the MSM detector (Liang et al, 2016;Goswami et al, 2020;Wang et al, 2021). This is because the vertical structure of the device has a shorter transmission distance, and the heterojunction detector has a built-in electric field that promotes the transmission of carriers (Wu et al, 2010;Xie et al, 2018).…”