High performance, flexible and room temperature grown amorphous Ga2O3 solar-blind photodetector with amorphous indium-zinc-oxide transparent conducting electrodes

Abstract

The quest for flexible and completely visible transparent solar-blind photodetector is the great motivation for next generation invisible security and photo-sensor application. Here, we have developed high performance and completely flexible solar blind photodetector using room temperature grown amorphous Ga2O3 thin film and unconventional amorphous indium-zinc-oxide (a-IZO) transparent conducting electrodes. The a-IZO transparent conducting electrodes are deposited using an optimized and unique RF superimposed DC sputtering which helps to achieve high optoelectronic properties with excellent mechanical flexibility. In contrast to conventional and highly reflective silver (Ag) metal electrodes, IZO offers transparency >85% in visible-IR. The solar-blind photodetector with a-IZO electrode shows high responsivity of 43.99 A W−1 and high external quantum efficiency of 2.18 × 104% in contrast to conventional Ag metal electrodes. The performance of the a-IZO/a-Ga2O3 photodetector is the highest among the reported amorphous Ga2O3 photodetector. Moreover, the flexibility of a-IZO electrode and conventional Ag metal electrode on a-Ga2O3 photodetector is investigated under repeated bending cycle. The a-IZO electrode shows excellent flexibility of the solar-blind photodetector and demonstrated a decrease in photocurrent by 28.6% under 30 cm bending radius and a 38.8% decrease in photocurrent even after 500 stretch/release cycles at 30 cm bending radius. However, the conventional Ag electrode shows complete failure on bending with 30 cm bending radius even on single cycle. The results demonstrated a-IZO thin film as a potential electrode for next generation flexible and visible transparent solar-blind photodetector.