Effect of Annealing on Ultrathin Zinc Oxide Films and Growth of Zinc Oxide Nanorods for Optoelectronics Applications

In this work, radio frequency sputtering was used to deposit an ultrathin (~25 nm) film of zinc oxide (ZnO) on the SiO2/Si substrate (~100 nm). ZnO thin film was annealed at 450 °C under argon atmosphere, and the effect of annealing was studied on the thin films for the growth of ZnO nanorods. X-ray diffraction (XRD) and atomic force microscopy (AFM) were used to study the surface morphology of the thin films. Hydrothermal method was used for the growth of ZnO nanorods on both annealed and unannealed thin films. The structural properties of the ZnO nanorods were characterized by XRD study and Field Emission Scanning Electron Microscopy with EDX. The effect of annealing was examined by comparing the parameters like growth and orientation of the ZnO nanorods. The impact of annealing ultrathin ZnO films on ZnO nanorod growth was negligible. The Ti/Au contact was deposited onto both samples using a thermal evaporator to create a metal semiconductor metal-based structure. Additionally, a semiconductor parameter analyzer was used to perform the electrical characteristics. The device was then exposed to 365 nm of ultra-violet light to study its photodetection capability, and as a result the device was proved to be a good photodetector. The obtained result further supports their wide applications in the area of electronic and optoelectronic devices.