High-Performance Metal-Organic Chemical Vapor Deposition Grown $\varepsilon$ -Ga2O3 Solar-Blind Photodetector With Asymmetric Schottky Electrodes

Abstract

In this letter we present a high performance $\varepsilon $ -Ga2O3 solar-blind photodetector (SBPD) with asymmetric Schottky electrodes. The $\varepsilon $ -Ga2O3 films were heteroepitaxially grown on ${c}$ -plane sapphire by metal-organic chemical vapor deposition (MOCVD). The SBPDs were fabricated in the form of lateral interdigitated Schottky electrodes composed of a Pt/Ti/Au metal stack and a Ti/Au metal stack. The SBPD shows a rectification ratio of ~ 102 with low dark current of 25 pA at ${V} = {6}$ V. A high photo-to-dark-current ratio of ${5.7}\boldsymbol {\times }{10}^{{4}}$ under 254 nm light illumination was measured. Furthermore, the SBPD exhibits an ultrahigh detectivity and external quantum efficiency of ${4.2}\boldsymbol {\times }{10}^{{14}}$ Jones and ${4.1}\boldsymbol \,\,{\times }\,\,{10}^{{4}}$ %, respectively. Most importantly, the SBPD possesses an ultrahigh responsivity of 84 A/W with a fast response speed of 100 ms, suggesting the promise of $\varepsilon$ -Ga2O3 in the future photodetector applications.