Flexible Solar-Blind Ga₂O₃ Ultraviolet Photodetectors With High Responsivity and Photo-to-Dark Current Ratio

Abstract

In this work, flexible solar blind Ga 2 O 3 ultraviolet photodetectors with high responsivity and photo-to-dark current ratio are demonstrated. The Ga 2 O 3 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 Ga 2 O 3 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°C, 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 10 5 , and the external quantum efficiency reaches 2.6 × 10 4 %, which is among the best reported Ga 2 O 3 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.

Solar-blind ultraviolet photodetector based on vertically aligned single-crystalline β-Ga2O3 nanowire arrays

“…Solar-blind region refers to the ultraviolet (UV) radiation with wavelengths of 200-280 nm from the sun, which is strongly absorbed by ozone in the atmosphere and almost nonexistent at the Earth's surface. Photodetectors (PDs) operating in this region without interference from solar radiation have a significant application value in civil and military areas [1][2][3][4]. Recently, Ga 2 O 3 has gained added interest as a promising candidate for solar-blind photodetection because of its wide bandgap of 4.5-4.9 eV, good chemical and thermal stability [5][6][7][8].…”

Ultrawide Band Gap Oxide Semiconductor-Triggered Performance Improvement of Perovskite Solar Cells via the Novel Ga2O3/SnO2 Composite Electron-Transporting Bilayer

“…Previous reports also determine that an enhanced V oc of PSCs could be achieved with the introduction of ultrawide band gap ETLs. 22,23 Among these ultrawide band gap semiconductor materials, because of its unique advantages such as inexpensiveness, excellent thermal and chemical stability, ultrawide forbidden bandwidth between 4.6 and 5.3 eV, high transmittance, and high electron mobility, 24,25 Ga 2 O 3 has developed rapidly recently and is common in the fabrication of photodetectors and other optoelectronic devices. However, it is rarely seen that Ga 2 O 3 is applied during the exploration of PSCs.…”

“…These semiconductor materials generally have superior light transmission characteristics, excellent charge-transporting properties, and appropriate energy band levels which are expected to have the ability to improve the selectivity of the electrode and thus reduce the carrier recombination in PSCs. Previous reports also determine that an enhanced V oc of PSCs could be achieved with the introduction of ultrawide band gap ETLs. , Among these ultrawide band gap semiconductor materials, because of its unique advantages such as inexpensiveness, excellent thermal and chemical stability, ultrawide forbidden bandwidth between 4.6 and 5.3 eV, high transmittance, and high electron mobility, , Ga 2 O 3 has developed rapidly recently and is common in the fabrication of photodetectors and other optoelectronic devices. However, it is rarely seen that Ga 2 O 3 is applied during the exploration of PSCs.…”

Recent Progress of Deep Ultraviolet Photodetectors using Amorphous Gallium Oxide Thin Films

“…For example, Li et al demonstrated a process of tuning temperatures (50–200 °C) during the Ga 2 O 3 film fabrication by RF‐magnetron sputtering, where the Ga 2 O 3 film remained amorphous structure. [ 46 ] At the highest temperature of 200 °C, the devices exhibited the best performance with responsivity of 52.6 A/W under 254 nm UV light illumination and the photo‐to‐dark current ratio of more than 10 5 . Interestingly, Wang et al fabricated Ga 2 O 3 film by RF‐magnetron sputtering with one step at a specific temperature range, where the film maintained a transitional state composing of both amorphous and crystalline phases.…”