Enhanced photoresponse of ZnO nanorods-based self-powered photodetector by piezotronic interface engineering.

Strain-induced piezopolarization can effectively engineer the interfacial electronic properties of a piezo-semiconductor junction, and thereby improve the performance of corresponding electronic devices. In this work, a metal–insulator–semiconductor (Pt/Al 2 O 3 /ZnO) based self-powered (SP) photodetector has been developed. The photodetector has sensitive response to the light illumination without any external bias. Applying an ultrathin dielectric layer and piezotronic effect are used as two effective strategies for interface engineering to enhance the photoresponse properties. The dielectric layer can significantly enhance the effective Schottky barrier height (SBH). In addition, the SBH can be actively modulated by the piezopolarization induced built-in electric field variation under compressive strains. Thus, the photoresponse properties of the SP photodetector are largely improved by the SBH enhancement. The responsivity and detectivity of the SP photodetector are increased by 2.77 times and 2.78 times, respectively under a compressive strain of −1.0%. According to the Schottky junction principle, it can be concluded that the piezotronic effect occurs strongly at the interface and gradually decays towards the quasi-neutral region of the junction. [ABSTRACT FROM AUTHOR]