Self-Powered n-SnO2/p-CuZnS Core-Shell Microwire UV Photodetector with Optimized Performance

Herein, a single-crystal SnO2 microwire photodetector (PD) is demonstrated with a fast response speed owing to a low concentration of point defects. However, the presence of surface defects (e.g., oxygen vacancies) still limits its optoelectronic performance. To further improve the photoresponse of such device, a core-shell p-n junction is constructed by simply coating a new p-type transparent conductive (CuS)(0.35):(ZnS)(0.65) nanocomposite film (CuZnS) on n-type SnO2 microwire. As a result, not only the surface of SnO2 is modified, but also a space charge depletion region is formed at the interface, leading to an enhanced on-off ratio of approximate to 1.3 x 10(3) and a faster speed of 45 mu s/1.17 ms (rise time/decay time) in comparison with the plain SnO2 microwire PD (on-off ratio of 30, response speed of approximate to 100 mu s/1.5 ms). Besides, the n-SnO2/p-CuZnS core-shell microwire could steadily work as a self-powered UV PD, with a maximum responsivity of 1.6 mA W-1 (at 0 V) and detectivity of 5.41 x 10(11) Jones (at 0.05 V) toward 315 nm, which suggests its great potentials as a high-performance self-powered UV photodetector.