Fabrication of p-type ZnSe:Sb nanowires for high-performance ultraviolet light photodetector application

Abstract

p-type ZnSe nanowires (NWs) with tunable electrical conductivity were fabricated on a large scale by evaporating a mixed powder composed of ZnSe and Sb in different ratios. According to the structural characterization, the Sb-doped ZnSe NWs are of single crystalline form and grow along the [001] direction. The presence of Sb in the ZnSe NWs was confirmed by XPS spectra. Electrical measurement of a single ZnSe:Sb NW based back-gate metal–oxide field-effect-transistor reveals that all the doped NWs exhibit typical p-type conduction characteristics, and the conductivity can be tuned over eight orders of magnitude, from 6.36 × 10−7 S cm−1 for the undoped sample to ∼37.33 S cm−1 for the heavily doped sample. A crossed p–n nano-heterojunction photodetector made from the as-doped nanostructures displays pronounced rectification behavior, with a rectification ratio as high as 103 at ±5 V. Remarkably, it exhibits high sensitivity to ultraviolet light illumination with good reproducibility and quick photoresponse. Finally, the work mechanism of such a p–n junction based photodetector was elucidated. The generality of the above result suggests that the as-doped p-type ZnSe NWs will find wide application in future optoelectronics devices.