Optical properties of ZnS_xSe_1−x alloy nanostructures and their photodetectors

Highlights: • ZnS_xSe_1−x alloy nanostructures were fabricated via a CVD process. • XRD, Raman spectra, and PL spectra confirm the formation of ZnS_xSe_1−x alloys. • The mechanism of photoconductivity is proposed and slow photoresponse is explained. - Abstract: ZnS_xSe_1−x alloy nanostructures have been successfully synthesized through a simple and effective chemical vapor deposition approach. X-ray diffraction measurements indicate that the ZnS_xSe_1−x alloys have a wurtzite-type hexagonal crystal structure. With the increase of the S content, their reflectance and photoluminescence spectra blue-shift continuously, further indicating the formation of the alloyed nanostructures. Raman spectra investigations demonstrate typical two-mode behavior. Moreover, the current versus voltage curve and photoresponse of the photodetectors were also tested. The results reveal that the photoconduction of the ZnS_xSe_1−x nanostructure is sensitive to the UV illumination. Furthermore, the mechanism of photoconductivity is proposed, and the reasons for slow photoresponse are suggested. All of these indicate that the ZnS_xSe_1−x alloy nanostructures have a broad application prospect in developing the ultraviolet radiation light sensors and photoelectrical switch devices