A self-powered p-CuBr/n-Si heterojunction photodetector based on vacuum thermally evaporated high-quality CuBr films

Recently, wide bandgap compound semiconductor materials have attracted much research interest owing to their great application potential. As most emerging oxide semiconductors are intrinsic n-type, it has become difficult to achieve p-type ones, limiting the development of pn junction-based devices. Copper bromide (CuBr) is a natural p-type semiconductor with a wide bandgap of approximately 3.0 eV and abundant reserves on the earth. In this work, we developed a vacuum thermal evaporation method to obtain high quality CuBr thin films. A self-powered p-CuBr/n-Si heterojunction photodetector that is highly sensitive to blue-violet wavelengths was constructed by preferential growth of CuBr thin films on n-Si substrates. The device has a significant response to 420 nm light, with a peak responsivity of 21.6 mA W-1 at 0 V (up to 271.5 mA W-1 at -0.5 V). Moreover, the photodetector exhibits excellent imaging ability under violet (420 nm) light. This work provides an effective approach to obtain high-quality wide bandgap CuBr films and self-powered heterojunction photodetectors. Violet heterojunction photodetectors based on p-CuBr/n-Si are prepared by the vacuum thermal evaporation technique. The photodetectors have a sensitive violet response with self-powered characteristics and excellent imaging capability.