UV enhanced white-light response based on p-Si/n-ZnO nanorod heterojunction photosensor

摘要

Two-regime photosensor has been fabricated from p-n junction between p-Si and n-ZnO nanorods. The junction is obtained by simply grown vertically-aligned ZnO nanorods on silicon substrate via hydrothermal method. As expected, the device response to visible and UV spectrum due to the band gap of silicon and ZnO, respectively. However, it is found that photoresponse to visible light can be enhanced under UV activation. Detailed mechanism behind the phenomena is proposed along with the photoluminescence results of defect states in ZnO nanorods. The trapped electrons from UV stimulation could be excited to conduction band by white light and contributed to the increase of the photocurrent of the device under white-light irradiation. This low-temperature solution growth ZnO nanorod-based UV-vis photosensor also presents reproducible results and fast recovery time. (C) 2019 Elsevier B.V. All rights reserved.