Effects of Ta concentration on microstructure, optical and optoelectronic properties of Ga2O3:Ta films

Ga2O3 material possesses extensive application potential and research value. Doping other elements into intrinsic Ga2O3 is one of the common methods to enhance its performance and is also a hot research direction nowadays. In this paper, Ta element was introduced into Ga2O3 material, and Ga2O3:Ta thin films with different Ta doping concentrations were fabricated using a dual-target RF co-sputtering system. The effects of Ta doping concentration on microstructure, optical, and optoelectronic properties of the films were meticulously investigated, and the optimal Ta doping concentration was determined. XPS results reveal that Ta entered Ga2O3 lattice with a +5 oxidation state, and combined with EDS results, it is inferred that Ta successfully partially substitutes Ga. XRD and XPS results indicate that when the sputtering power of Ta2O5 is 30 W, corresponding to a Ta doping concentration of 2.39 at.%, the film exhibits enhanced crystallinity. The Ga2O3-based MSM detector prepared under this condition demonstrates superior stability and detection sensitivity. Additionally, it also exhibits stable photoresponse to 365 nm light. This work promotes the application of Ga2O3 material and provides new insights into improving the stability and performance of ultraviolet photodetectors.