Band Gap Engineering of AlYN Films for Solar-Blind Ultraviolet Photodetection

Abstract

Aluminum nitride (AlN) has been proven as a potential photoelectric material with high breakdown field strength, excellent thermal conductivity, and stable physical properties. However, its ultrawide intrinsic band gap (6.2 eV) prohibits the direct application of AlN as an optical absorption layer for solar-blind ultraviolet (SBUV) detectors. To solve this problem, AlYN thin films with a SBUV absorption cut-off edge of 264 nm were prepared first by energy band engineering using yttrium (Y) as the dopant, based on which a photovoltaic detector with a p-Gr/i-AlYN/n-Si structure was fabricated and exhibited excellent performance of SBUV detection at 0 V bias, including an extremely short rise time (tr) of 20 ms, a decay time (td) of 60 ms, an ultrahigh detectivity (D*) of 5.09 × 1012 Jones, a responsivity (R) of 13 mA/W, a maximum external quantum efficiency (EQE) of 6.69%, and a rejection ratio (R255nm/R310nm) of 245. This work has great value as a reference for the preparation of high-performance AlN-based SBUV detectors.