Insight into piezoelectricity modulation mechanism of ZnO doped with Y ions

Abstract

ZnO is a performance-rich material due to its unique coupling of piezoelectricity and semiconductor properties. However, the intrinsic piezoelectric screening effect of ZnO weakens the electromechanical conversion efficiency and greatly limits its application. To solve this dilemma, it has been recently shown that the piezoelectricity of ZnO can be enhanced by doping to suppress the screening effect, but the exact modulation mechanism remains an open question. Here, we take a new perspective to investigate the piezoelectricity modulation mechanism of Y-doped ZnO at the atomic scale. Both the experimental and simulation results verify the successful suppression of the piezoelectric screening effect. The underlying modulation mechanism of Y-doped ZnO is revealed from the perspective of carrier concentration, work function and bandgap width, respectively. The prepared Y-doped ZnO demonstrates a 97.8%-dropped carrier concentration and a significant improvement (nearly 8.5-fold) in the output performance. This work provides theoretical guidance for the design of ZnO-based piezoelectric devices and is expected to be generalized to other piezoelectric materials, which is of great significance for improving the energy conversion efficiency of piezoelectric devices.