High gain broadband photoconductor based on amorphous Ga2O3 and suppression of persistent photoconductivity

Abstract

In this work, a new type of photoconductor with high responsivity and gain over a wide spectral range of DUV to NIR using a wide band gap amorphous gallium oxide (a-Ga₂O₃) thin film was reported for the first time. The responsivity (gain) at deep UV-250, UV-350, VIS-525 and NIR-850 nm is as high as 1099 (5438), 265 (936), 205 (483) and 122 A W⁻¹ (178), respectively. More interestingly, we demonstrate that a novel “thermal relaxation” (TR) process (short-time heating) can effectively reduce the dark current and improve the response recovery time from hours to seconds without reducing the gain of the a-Ga₂O₃ detector. The mechanism related to oxygen vacancies and thermal energy and tail state excitation is proposed to explain our experimental phenomena. This result suggests that amorphous Ga₂O₃ films have potential applications in high-performance broadband photodetecting devices.