Enhanced Responsivity and Optoelectronic Properties of Self-Powered Solar-Blind Ag2O/β-Ga2O3 Heterojunction-Based Photodetector with Ag:AZO Co-Sputtered Electrode
Younghwa Yoon, Sangbin Park, Taejun Park, Hyungmin Kim, Kyunghwan Kim, Jeongsoo Hong
Abstract
A Ag:AZO electrode was used as an electrode for a self-powered solar-blind ultraviolet photodetector based on a Ag2O/β-Ga2O3 heterojunction. The Ag:AZO electrode was fabricated by co-sputtering Ag and AZO heterogeneous targets using the structural characteristics of a Facing Targets Sputtering (FTS) system with two-facing targets, and the electrical, crystallographic, structural, and optical properties of the fabricated thin film were evaluated. A photodetector was fabricated and evaluated based on the research results that the surface roughness of the electrode can reduce the light energy loss by reducing the scattering and reflectance of incident light energy and improving the trapping phenomenon between interfaces. The thickness of the electrodes was varied from 20 nm to 50 nm depending on the sputtering time. The optoelectronic properties were measured under 254 nm UV-C light, the on/off ratio of the 20 nm Ag:AZO electrode with the lowest surface roughness was 2.01 × 108, and the responsivity and detectivity were 56 mA/W and 6.99 × 1011 Jones, respectively. The Ag2O/β-Ga2O3-based solar-blind photodetector with a newly fabricated top electrode exhibited improved response with self-powered characteristics.