Heteroepitaxial α‐Ga<sub>2</sub>O<sub>3</sub> Thin Film‐Based X‐Ray Detector with Metal–Semiconductor–Metal Structure
Minje Kim, Sunjae Kim, Ji‐Hyeon Park, H Cho, Se Hoon Gihm, Dae‐Woo Jeon, Wan Sik Hwang
Abstract
This study explores the potential of 700‐nm‐thick heteroepitaxial α‐Ga 2 O 3 thin films on c‐plane sapphire substrates for X‐ray detector applications. The crystal quality and optical bandgap of the heteroepitaxial α‐Ga 2 O 3 thin films are comparable to those of high‐quality α‐Ga 2 O 3 thin films. The α‐Ga 2 O 3 thin film X‐ray detector with a metal–semiconductor–metal structure exhibits a charge neutral point shift, resulting in a short‐circuit current density of 9.07 nA cm −2 and an open‐circuit voltage of –1.2 V. The detector achieves the highest signal‐to‐noise ratio of 973 at 0 V, while the maximum sensitivity (14.7 μC Gy air −1 cm −2 ) occurs at 10 V. The proposed X‐ray detector demonstrates a reliable transient response and long‐term robustness, suggesting the promise of heteroepitaxial α‐Ga 2 O 3 for low‐cost, high‐quality, large‐area X‐ray detectors.