High-performance CdS@CsPbBr3 core–shell microwire heterostructure photodetector

Abstract

A core–shell heterojunction has been developed to fabricate efficient optoelectronic devices by optimizing the light absorption and promoting the generation and extraction of charge carriers. Herein, the CdS@CsPbBr3 core–shell microwire (MW) heterojunction was structured via a two-step chemical vapor deposition and was further used to fabricate a UV–Vis photodetector. The photodetector performance is greatly dependent on the thickness of the CsPbBr3 shell. Growth time of 60 min could produce about 80 nm thick CsPbBr3 shell with excellent coverage and adhesion, resulting in optimized performance parameters. As compared with bare cadmium sulfide (CdS) MW photodetector, the CdS@CsPbBr3 core–shell MW heterojunction photodetector exhibits relatively high ratio of photocurrent and dark current (104), much higher light responsivity (319.79 A W−1) and faster response time (6.6 ms). The responsivity is 3.3 times to the value of bare CdS photodetector and the photocurrent increases nearly 10 times. The significant performance parameters mainly result from the formation of a type-II energy band structure and the reduction of the defects states on CdS surface, leading to the obviously improved carriers transport process. The results indicate that the CdS@CsPbBr3 core–shell MW heterojunction is a promising potential candidate to construct high-performance electronic and optoelectronic devices.