Stability improvement of Cu(ii)-doped ZnS/ZnO photodetectors prepared with a facile solution-processing method

Abstract

The main challenge of ZnO-based photodetectors is correlated with the difficulty of achieving both high photodetection performance and good environmental stability due to the deteriorated effect of photocorrosion under light illumination. Here, we presented the potential solution by applying Cu²⁺-doped ZnS as protective coatings on ZnO nanorods based on solution synthesis, where the systematic investigations on such core/shell nanostructures were performed by conducting crystallographic, morphological, compositional, photoluminescent, and light-absorption characterizations. In addition, the designed Cu²⁺-doped ZnS/ZnO-based photodetector demonstrated the substantial improvement of the specific detectivities reaching 99.3 × 10¹² and 127.2 × 10¹² cm Hz^1/2 W⁻¹ under the light illuminations of 365 nm and 420 nm, which were more than 22 times and 45 times beyond those of bare ZnO, respectively. It should be noted that the improved environmental stability for long-term utilization was revealed, where the photoresponsivity was sustained to be above 95.4% for lasting 60 days. Significantly, the present study provided a facile approach to advance the development of high-performance, broadband and reliable photodetector designs.