α-Ga₂O₃ Photodetector With Responsivity Over A/W Level Based on Sn-Assisted Mist-CVD

In recent years, $\alpha $ -Ga2O3 and $\alpha $ -Ga2O3-based photodetectors (PDs) have garnered significant attention due to their unique advantages in deep-ultraviolet (DUV) photodetection. However, the growth of $\alpha $ -Ga2O3 thin films via the mist chemical vapor deposition (mist-CVD) method faces several challenges, such as inferior crystallization quality, which impedes the development of high-performance PDs. In this study, we successfully achieved high-quality $\alpha $ -Ga2O3 epitaxy on the $\alpha $ -Al2O3 substrate using the tin (Sn)-assisted mist-CVD technique. A DUV PD was subsequently fabricated on the epitaxial film, and its detection performance was thoroughly evaluated. The PD achieved a photocurrent of up to 175.40 nA and a signal-to-noise ratio (SNR) of 76.5 dB. Most notably, it also exhibited a high responsivity of up to 3.76 A/W, an external quantum efficiency (EQE) of 1841.12%, and a detectivity of $1.8\times 10^{{11}}$ Jones, underscoring the potential of the Sn-assisted mist-CVD method for advancing the development of next-generation $\alpha $ -Ga2O3 DUV PDs.