Transparent and flexible selenium nanobelt-based visible light photodetector

We report a synthesis of single-crystal [001] oriented selenium nanobelts (SeNBs) through a simple vacuum evaporation at 250 degrees C. The width and thickness of the SeNBs are in the range of 100-800 nm and 20-90 nm, respectively. I-V analysis of an individual SeNB based field effect transistor (FET) reveals typical p-type electrical conduction. The hole mobility and concentration are respectively estimated to 0.63 cm(2) (V s)(-1) and 9.35 x 10(16) cm(-3). The p-type electrical characteristics can be explained by the surface termination model, according to which, H- or OH- termination can induce a defect level slightly above the valance band maximum (VBM). A fully transparent and flexible visible light photodetector assembled on a polyethylene terephthalate (PET) substrate shows a high sensitivity to visible light illumination, with sensitivity and conductive gain as high as 3.27 x 10(4) A W-1 and 6.77 x 10(4) respectively. Furthermore, the device also exhibits a stable performance and good reproducibility under different bending conditions. The high-performance visible light photodetector would enable application opportunities in future flexible and transparent electronics.