Improved UV-Sensing of Au-Decorated ZnO Nanostructure MSM Photodetectors

In this work, we use gold (Au) nanoparticles (NPs) to modify zinc oxide (ZnO) nanostructures and improve the performance of ultraviolet (UV) metal–semiconductor–metal (MSM) photodetectors (PDs). The surface morphology, crystal performance, optical characteristic, and electrical property of the nanostructures were determined by using several instruments [e.g. X-ray diffractometer, field-emission scanning electron microscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and semiconductor parameter analyser]. Single-crystalline one-dimensional (1-D) nanorods (NRs) with hexagonal wurtzite structures were obtained via a facile hydrothermal synthetic route. The ZnO and Au/ZnO NRs with direct current magnetron sputtering times (i.e. 0 and 10 s) were labelled ZOA-0 and ZOA-1 samples, respectively. When the applied voltage was 1 V, ZOA-0 and ZOA-1 samples had dark currents (
${I} _{dark}$
) of
$2.21\times10$
⁻⁸
and
$3.28\times10$
⁻⁹
A, respectively, in the photocurrents (
${I} _{ph}$
) of
$1.35\times10$
⁻⁷
and
$4.33\times10$
⁻⁶
A, respectively, under UV irradiation. The
${I} _{ph}/{I} _{dark}$
ratios of ZOA-0 and ZOA-1 NRs were 6 and 1320, respectively. As a result, the adsorption of Au on ZnO NRs can increase the conductivity of UV MSM PDs and improve the responsivity of devices for UV-sensing.