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

Abstract

AbstractHerein, 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 ≈1.3 × 103 and a faster speed of 45 µs/1.17 ms (rise time/decay time) in comparison with the plain SnO2 microwire PD (on‐off ratio of 30, response speed of ≈100 µs/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 × 1011 Jones (at 0.05 V) toward 315 nm, which suggests its great potentials as a high‐performance self‐powered UV photodetector.