Effects of Mg Component Ratio on Photodetection Performance of MgGa2O4 Solar‐Blind Ultraviolet Photodetectors

Abstract

Mg x Ga2O4 epitaxial films with different Mg component ratios (x = 0.6, 0.8, 1, 1.1, and 1.4) and their metal–semiconductor–metal solar‐blind ultraviolet (SBUV) photodetectors are prepared on c‐face sapphire by metal–organic chemical vapor deposition (MOCVD). The structure, composition, crystalline quality, and optical properties of the Mg x Ga2O4 thin films have been investigated in detail. It can be found that five Mg x Ga2O4 thin films have the spinel structure with a similar bandgap of ≈5.15 eV, and the highest crystalline quality is observed in Mg x Ga2O4 with x = 1. Besides, photodetector based on Mg x Ga2O4 film with x = 1 has the highest responsivity, the largest UV–visible rejection ratio, and the fastest response speed. As the content of Mg deviates from the stoichiometric ratio of MgGa2O4, the crystalline quality of the Mg x Ga2O4 thin film is reduced, and their photoelectric response characteristics are deteriorated. This work indicates that MgGa2O4 is a promising candidate for the applications in high‐performance solar‐blind ultraviolet photodetectors.