High-performance self-driven solar-blind ultraviolet photodetector based on Ga2O3/KNNM semiconductor-ferroelectric heterojunction

Abstract

Ga2O3-based solar-blind ultraviolet (UV) photodetectors have attracted extensive attention owing to their enormous potential in civilian and military fields. However, yet poor responsivity (R) and detectivity (D∗) of Ga2O3-based solar-blind UV photodetectors have hindered their practical applications. In this work, Ga2O3/K0.5Na0.5(Nb0.94Mn0.06)O3 (KNNM) heterojunction photodetectors with a type-II energy band configuration were designed and fabricated. The Ga2O3/KNNM heterojunction device shows a significantly higher performance (R = 13.28 mA/W, D∗ = 1.87 × 1011) at zero bias than the single-layer Ga2O3 (R = 6.75 mA/W, D∗ = 6.71 × 1010 Jones) and KNNM (R = 0.04 mA/W, D∗ = 7.14 × 108 Jones) based devices. The superior performance is attributed to the enhanced separation of photogenerated carriers caused by the constructive coupling of ferroelectric depolarization electric field in the KNNM ferroelectric material and Ga2O3/KNNM heterojunction built-in electric field. Under weak light illumination, the Ga2O3/KNNM heterojunction photodetector in the upward poling state shows the highest R (33.48 mA/W) and D∗ (4.71 × 1011 Jones) under zero bias toward 245 nm wavelength UV light. This work showcases Ga2O3/KNNM heterojunction as a promising candidate for constructing high-performance self-driven solar-blind ultraviolet photodetectors.