Structural, electrical, and optical properties of Ag2ZnSnSe4 for photodetection application

Abstract

Ag2ZnSnSe4 (AZTSe) thin films were synthesized using a simple solution approach combined with a post-selenization technique. A single phase of the AZTSe film with kesterite structure and high crystal quality was obtained at the optimized selenization temperature and time. The AZTSe film showed an optical bandgap of 1.4 eV, an n-type conduction with an electron concentration of 5.7 × 1015 cm−3, and a mobility of 9.1 cm2 V−1 s−1. An optimized n-type AZTSe film was fabricated on a p-GaN/sapphire to form an n-AZTSe/p-GaN heterojunction. The current–voltage measurement of the n-AZTSe/p-GaN heterojunction photodetector showed good rectification characteristics. The response wavelength of the photodetector covered a wide range from ultraviolet to infrared (370–960 nm). The response peak was located at 810 nm with a responsivity of 2.9 × 10−4 A/W.