Ceramics International | 2021
Substrate-bias-aided preparation and properties of amorphous gallium oxide films and their deep-ultraviolet photodetectors
Abstract
Abstract Amorphous gallium oxide (a-GaOx) thin films are fabricated via magnetron sputtering at room temperature by regulating the substrate bias voltage (Vs) in a wide range (0\xa0~\xa0-184\xa0V). The effect of Vs on the performance of a-GaOx films and their photodetector devices, such as the chemical composition, optical, morphological, and electrical properties, are systematically investigated. It s found that both the refractive index and the film relative mass density are highly dependent on the Ga/O ratio that can be effectively modified by the Vs. And the subband trap density or/and microvoid defects in a-GaOx films can be largely reduced under a well-selected Vs. The deep-ultraviolet photodetectors based on the optimized a-GaOx thin films show a responsivity of nearly 13 A/W with an ultrahigh UV/vis. rejection ratio. The research suggests that substrate bias voltage may be a feasibly subsidiary method for low-temperature magnetron sputtering technology with respect to the quality control of a-GaOx films.