Fabrication and characterization of copper oxide-silicon nanowire heterojunction photodiodes

摘要

In this study, copper oxide (CuO) thin film/silicon (Si) nanowire heterojunctions have been fabricated and their optoelectronic performances have been investigated. Vertically aligned n-type Si nanowires have been fabricated using metal-assisted etching (MAE) technique. CuO thin films were synthesized by the sol-gel method and deposited onto the nanowires through spin-coating. Fabricated nanowire heterojunction devices exhibited excellent diode behaviour compared to the planar heterojunction control device. The rectification ratios were found to be 10~5 and 10~1 for nanowire and planar heterojunctions, respectively. The improved electrical properties and photosensitivity of the nanowire heterojunction diode was observed, which was related to the three-dimensional nature of the interface between the Si nanowires and the CuO film. Results obtained in this work reveal the potential of Si nanowire-based heterojunctions for various optoelectronic devices.