Au-Mediated Surface Plasmon Enhanced Ultraviolet Response of p-Si/n-ZnO Nanorods Photodetectors

• Published in: IEEE photonics technology letters Vol. 26; no. 10; pp. 1023 - 1026
• Main Authors: Hwang, Jun-Dar, Lai, M. J., Chen, H. Z., Kao, M. C.
• Format: Journal Article
• Language: English
• Published: New York IEEE 15.05.2014; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Conduction band; Covering; Gold; Nanoparticles; Nanorods; Photoconductivity; Photodetectors; Plasmons; Solar energy; Substrates; Surface treatment; Ultraviolet; Zinc oxide; ZnO nanorod; Au nanoparticles; Surface plasmon resonance; heterojunction photodetectors
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/LPT.2014.2312734

Surface plasmon resonance mediated by Gold (Au) nanoparticles (NPs) was employed to enhance the ultraviolet (UV) response of p-Si/n-ZnO nanorod (NR) heterojunction photodetectors (HPDs). In the ZnO NRs with Au NP covering, the photoluminescence spectrum shows that the band-to-band emission of ZnO (384 nm) is increased by a magnitude of 3, and the deep-level emissions (450-700 nm) are drastically decreased as compared with HPDs without coverings of Au NPs. Such a result increases UV-to-visible rejection ratio from 214 to 6180 and it attributes that the defect-level emissions of ZnO induce surface plasmon resonance in Au NPs and then enhances the emissions, exciting a large quantity of electrons crossing over the Au NP/ZnO interface barrier. Consequently, these electrons are transferred to the ZnO conduction band from the Au NPs, causing a photocurrent gain and the quantum efficiency is as high as 1157% at 2 V reverse bias.