Tuning oxygen vacancies and improving UV sensing of ZnO nanowire by micro-plasma powered by a triboelectric nanogenerator

Plasma technology is a common method in surface passivation and improving device performances. However, the requirement of expensive instruments makes it difficult to integrate into a device system and work together with devices. In this paper, a device system has been established by introducing a micro-plasma, which is powered by the high voltage of a triboelectric nanogenerator (TENG). It is demonstrated that the oxygen vacancies on ZnO nanowire are passivated by the micro-plasma step-by-step, as the operation time of TENG is controlled. After the oxygen vacancies are passivated by micro-plasma, the intrinsic resistance of the ZnO nanowire is increased significantly. As for the UV photodetector performances after micro-plasma passivation, the on-off ratio, the gain and bandwidth product, and the recovery speed are improved 254, 111, and 2651 times, respectively. The mechanisms of tuning oxygen vacancies and improving UV sensing properties of ZnO nanowire by micro-plasma have been discussed. Given the advantages of low cost, flexible modes, and simple operation of TENG, the TENG-based micro-plasma technology can be integrated into a device system to passivate surface defects and improve device performances, which has potential applications in developing smart and multifunctional sensors network in the era of internet of things.