Study on the PECVD-hetero-grown β-Ga2O3 thin film and temperature-modulated solar-blind UV photodetection

Abstract Using a convenient and low-cost plasma-enhanced chemical vapor deposition (PECVD) technique, uniform Ga2O3 thin films were hetero-grown on c-plane sapphire substrates at different temperatures, with root mean square (RMS) roughness as low as 2.71 nm and a growth rate of up to 1121.30 nm/h; and then the solar-blind UV photodetection performances were discussed in detail. Metal-semiconductor-metal (MSM) solar-blind UV photodetectors based on the five Ga2O3 films prepared at different temperatures exhibit ultra-low dark currents (Idark) ranging among 22-168 fA. Under the illumination of 254 nm UV light, the photodetector prepared by the film grown at 820 ℃ possesses the highest performance with a high photo-to-dark current ratio (PDCR) of 1.47×105, a low rise/fall time of 0.067/0.13 s, a specific detectivity (D*) of 3.56×1012 Jones, and a linear dynamic range (LDR) of 92.89 dB. In all, the results in this work may well provide a referable method for growing cost-effective and ultralow-noise Ga2O3 thin films; as well as achieving decent solar-blind UV sensing application.