Performance enhancement in ZnO nanowire based double Schottky-barrier photodetector by applying optimized Ag nanoparticles

Abstract

In this work, a UV photodetector made of a ZnO nanowire with double Schottky Barrier (SB) contacts was fabricated by an electric field guided assembly process. Then the Ag-nanowire composite in the device was achieved through an RF metal sputtering method. Under 5 V bias, the values of responsivity and photoconduction gain of the final device could reach up to 4.91 × 10⁶ A W⁻¹ and 1.67 × 10⁷, respectively. Surprisingly, the device covered with optimized Ag nanoparticles still presented its spectrum selectivity in the visible-blind band. The nonlinear behavior at small bias was governed by the reversely biased SB contacts. After introducing Ag nanoparticles, the localized surface plasmon resonance (LSPR) induced absorption could account for the enhanced performance. In addition, the increased dark current was attributed to the involuntary introduction of localized gating effect near the contacts.