Improved Current Extraction of Cu/Si Nanowire Heterojunctions for Self-Powered Photodetecting with Insertion of MoOx Quantum Dots Film

MoO x quantum dots were inserted between the Si nanowires (SiNWs) and Cu contacts to form the MoO x /SiNW heterojunctions via the low-temperature solution process. The common Schottky heterojunction of Cu/SiNWs is used as the referred device, and the photoelectric characteristics of Cu/MoO x /Si structures are detailedly investigated. The results indicate that the inset of MoO x between Cu and SiNWs obviously enhances photoelectric conversion efficiency from 1.58 to 3.92%, and photodetection characteristics have also improved compared to the referred device. We attribute these experimental findings to the fact that the incorporation of MoO x quantum dots into the Cu/Si heterojunction could enhance the transport of holes and inhibit the injection of electrons from Si into the top Cu electrode. In addition, it is believed that such an improved performance also comes from the improved optical absorption as well as the optimized carrier transfer and collection capability of MoO x /SiNW radial heterojunctions.