Light trapping in ZnO nanowires to control ultraviolet photodetection responsivity

Abstract

The ZnO planar thin-layer usually suffers from low-light absorbing ability because of its short transmission path of incident light. Herein, we demonstrate a series of high-performance ZnO nanowires array ultraviolet photodetectors via hydrothermal synthesis. In conjunction with ZnO nanowires array, which shows strong light trapping effect, the light absorbing ability of ZnO photodetectors is greatly enhanced. Using optical transmission and photocurrent measurements on ZnO photodetectors, it is shown that the ordered arrays of ZnO nanowires increase the light responsivity. Furthermore, in the case of nanowires length growth, it is confirmed that the photon path length and path length enhancement factor also increases, thus reducing the loss of light, and reflecting a large amount of light on ZnO film, which is then collected. The light trapping effect of ZnO nanowires ultraviolet photodetectors exhibits higher photo-to-dark current ratio above 104, where photoresponsivity reaches 14.50 A W−1 and excellent detectivity (~1012 Jones). The light trapping effect of nanomaterials is applied to the research of photoelectric detectors, which provides a new perspective for photoelectric materials.