Performance optimization of p-n homojunction nanowire-based piezoelectric nanogenerators through control of doping concentration

Abstract

This paper demonstrates a series of flexible transparent ZnO p-n homojunction nanowire-based piezoelectric nanogenerators (NGs) with different p-doping concentrations. The lithium-doped segments are grown directly and consecutively on top of intrinsic nanowires (n-type). When characterized under cyclic compressive strains, the overall NG performance is enhanced by up to eleven-fold if the doping concentration is properly controlled. This improvement is attributable to reduction in the mobile charge screening effect and optimization of the NGs' internal electrical characteristics. Experimental results also show that an interfacial MoO3 barrier layer, at an optimized thickness of 5–10 nm, reduces leakage current and substantially improves piezoelectric NG performance.