Enhanced UV photodetectivity in solution driven ZnO nanosheets via piezo-phototronic effect

摘要

Here in, we report the fabrication of thin two dimensional (2D) ZnO nanosheets (NSs) flexible piezo-phototronic ultraviolet (UV) photodetector (PD). The morphological and optical propertiesof theas-synthesizedZnONSs is characterizedindetail.TheflexibleAgeZnONSs-Ag lateral PDs are fabricated on the polyethylene terephthalate (PET) substrate. A striking photoresponse isobservedfor 2D-ZnOunderUVillumination. Furthermore,by introducing astrain(inthe form of bending) the photocurrent and responsivity of this PD can be modulated via piezophototronic effect, emerging from the ZnO nanosheets. The photocurrent enhancement under bending could be attributed to the piezo polarization charges produced at ZnO/Ag interface due to strain. This piezo polarization charges result in the modulation of Schottky barrier (SB) height at the semiconductor/metal interface and induce improved photogenerated charge carriers and reduced recombination probability to result enhanced performances from the ZnO NSs photodetector. The physical mechanisminvolved in the enhancement of photocurrent via piezo-phototronic is proposed to explain change in SB height at semiconductor/ metal interfaceusing thebanddiagrams.This resultsdemonstratesanefficientprototypeof the piezo-phototronic PD based on thin ZnONSs,which provides an effective pathway to enhance the performance of optoelectronic devices.