The high-speed ultraviolet photodetector of ZnO nanowire Schottky barrier based on the triboelectric-nanogenerator-powered surface-ionic-gate

Abstract

Nanowires have a high specific surface area and high surface activity, and the surface states are key factors controlling the nanowire Schottky barrier. Therefore, adjusting the surface states is an important strategy for developing high-performance electronic and optoelectronic devices based on nanowire Schottky barriers. Here, a surface-ionic-gate modulation technique was developed to modulate the surface states and Schottky barrier of nanowires, based on the gas discharge induced by triboelectric nanogenerators (TENGs). It is demonstrated that the Schottky barrier height and electrical transport characteristics of the Ag/ZnO nanowires can be modulated by effectively controlling the surface states. The experimental results from different atmospheres show that O2− ions and electrons generated by gas discharge can form local ions on nanowires surface, which is the source for modulating surface states. Reversible modulation of the surface states and barrier height could be achieved by combining the surface-ionic-gate modulation with ultraviolet (UV) light. In addition, the recovery time of the ZnO nanowire Schottky barrier UV photodetector was reduced from 87 s to 0.3 s using the surface-ionic-gate modulation technique, the recovery speed increased 290 times, making it a universal method for achieving fast UV detection in different environments, such as in air, in oxygen, and in nitrogen. The TENG-based surface-ionic-gate modulation technique proposed here can modulate the surface states of nanowires in real time and in situ. This provides a novel method to study the dynamic generation and relaxation process of surface states and to develop high-performance electronic and optoelectronic nanodevices with broad application prospects.