A sandwich-structured surface plasmon ultraviolet photodetector based on ZnO thin film

Abstract

In this article, novel sandwich-structured surface plasmon ultraviolet (UV) photodetectors based on ZnO thin films with engineered rear metal electrode were fabricated by radio-frequency magnetron sputtering. An exhaustive study about the impact of a dissimilar metallic layer (Au and Pt) on the structural, optical, and electrical properties of the device was carried out. The carrier collection property of the sandwich structure devices has the advantages of horizontal and vertical joint collection. In theory, adding a new metal semiconductor layer introduces a contact area and increases the resistance. An ultra-low dark noise current of less than 2.0 × 10–7 A and a responsivity exceeding 1.6 A/W were achieved with the prepared ZnO-based UV-PDs in the rear metallic electrode mode. The devices based on the ZnO/Pt/ZnO and MgZnO/Pt/MgZnO sandwich structures show high responsivity and fast response. This study provides a depletion layer width method for the fabrication of high-response UV photodetectors for surface plasmon-based materials by integrating metal semiconductor nanostructures. A homogeneous two-layer UV photodetector is constructed, which changes the traditional single-layer device structure and overcomes drawbacks of the single device structure.