Doped Zno thin films : fabrication, characterizations and performance analysis as ultraviolet photodetectors

Abstract

ZnO has emerged as the subject of research for many optoelectronic applications in recent years, because it is nontoxic, abundant, chemically stable, and biocompatible. Due to its direct wide band gap of 3.37 eV and a large exciton binding energy of 60 meV at room temperature, it has been explored by many researchers for devices like light emitting diode, photodetectors, lasers, solar cells etc. Moreover, as compared to other semiconductor materials such as GaN, SiC, and AlN, ZnO offers several fundamental advantages such as high breakdown strength, high temperature operation, and transparency in the visible region. In this work, the growth and characterization of doped ZnO based thin films by dual ion beam sputtering system was performed for the realization of high performance ZnO based ultraviolet photodetectors. The material study in this work focused on optimal deposition conditions of ZnO thin films with single dopant as gallium (Ga) and phosphorus (P) and codoping with lithium and phosphorus (Li-P) both. The structural, morphological, optical and electrical properties of these thin films has been studied by various characterizations. After the material optimizations the ultraviolet photodetectors were fabricated and spectral responses were analyzed while correlating with the properties of the thin films.