The unsaturated photocurrent controlled by two-dimensional barrier geometry of a single ZnO nanowire Schottky photodiode

In this letter, the I-V curve of a single ZnO nanowire assembled by dielectrophoresis was measured, which indicated that a back-to-back Schottky barrier structure was formed. Under ultraviolet light illumination, the photocurrent of the ZnO nanowire Schottky photodiode was unsaturated, and its differential conductivity increased with the increase of bias. A two-dimensional Schottky barrier geometry model was introduced to describe the separation of photogenerated electron-hole pairs in the depletion layer, which can well explain the unsaturated photocurrent property. In addition, the corresponding photocurrent equation was obtained, which was in good agreement with the experimental results.