Chlorine-doped n-type CdS nanowires with enhanced photoconductivity

Cl-doped n-type CdS NWs with single-crystal wurtzite structure and [2 (1) over bar(1) over bar1] growth direction were synthesized by using CdCl2 as the dopant via a thermal co-evaporation method. By controlling the Cl vapor pressure during the growth, the conductivity of the CdS: Cl NWs can be tuned in a wide range of five orders of magnitude. A nano-photodetector based on the CdS: Cl NWs shows high sensitivity to visible light with excellent stability and reproducibility. Significantly, the photoconductivity of the CdS NWs is greatly enhanced by Cl doping and the responsivity and photoconductive gain of the CdS: Cl NWs have substantially increased compared with the undoped CdS NWs. Further study also demonstrates the polarization-dependent photoconductivity of the CdS: Cl NWs. It is expected that the CdS: Cl NWs with tunable optoelectronic properties will have important applications in high-performance nano-optoelectronic devices.