Ultrahigh Detectivity and Wide Dynamic Range Ultraviolet Photodetectors Based on BixSn1-xO2 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 BixSn1-xO2 (0.017 < x < 0.041) films show a detectivity of 6.1 × 1015 Jones at 280 nm and a quantum efficiency of 2.9 × 104 %. 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 BixSn1-xO2 films can serve as a high performance UV photodetector.