Reversible conversion between Schottky and ohmic contacts of zinc oxide microwire under piezoelectric potential manipulation

The energy barrier height of ZnO microwire electrical contacts is tuned by inducing piezoelectric polarization charges at the local metal-semiconductor interface when a mechanical deformation is applied to the ZnO microwire. Strain is introduced in the individual ZnO microwire by compressive stress applied along the axial direction, which controllably bends the microwire, observed in an optical microscope. As a result, the metal-semiconductor local contact can transform from Schottky to Ohmic and vice versa. This work demonstrates a simple method for controlling the electrical properties of ZnO nanowires to achieve reversible tuning between Schottky and Ohmic contact on one device by combining in-situ measurement with mechanical manipulation. This can contribute to the development of multifunctional and Ohmic/Schottky-based sensors, switches, rectifiers, and other functional electronic devices.