Ultrahigh Detectivity and Wide Dynamic Range Ultraviolet Photodetectors Based on BiSnO Intermediate Band Semiconductor.

The ultraviolet (UV) photodetectors have significant applications different fields. High detectivity, high responsivity and wide active area are required to probe a weak UV light in actual ambient. Unfortunately, most practical UV photoconductors based on wide bandgap semiconductor films can hardly have both a high responsivity and a low dark current density. In this study, the intermediate band engineering in semiconductor has been proposed try to solve this problem. The intermediate band UV photodetectors based on BiSnO (0.017 < x < 0.041) films show a detectivity of 6.1 × 10 Jones at 280 nm and a quantum efficiency of 2.9 × 10 %. The dynamic range is 195 dB, which is much higher than other UV photodetector. The recovery time is about 1 s after exposing device into ethanol steam. Our results demonstrate that the intermediate band semiconductor BiSnO films can serve as a high performance UV photodetector.