High performance photodetector based on CdS/CdS_0.42Se_0.58nanobelts heterojunction

The ternary alloy CdS_xSe_1-xcombines the physical properties of CdS and CdSe, and its band gap can be adjusted by changing the element composition. The alloy has charming photoelectric properties as well as potential application value in photoelectric devices. In this work, the CdS/CdS_0.42Se_0.58nanobelt (NB) heterojunction device was prepared by chemical vapor deposition combined with a typical dry transfer technique. The heterojunction photodetector shows high light switching ratio of 6.79 × 10⁴, large spectral responsivity of 1260 A W^-1, high external quantum efficiency of 2.66 × 10⁵% and large detectivity of 7.19 × 10¹⁵cm Hz^1/2W^-1under 590 nm illumination and 3 V bias. Its rise and decay time is about 45/90μs. The performance of the heterojunction photodetector was comparable or even better than that of other CdS(Se) based photodetector device. The results indicate that the CdS/CdS_0.42Se_0.58NB heterojunction possesses a promising potential application in high performance photodetectors.