Optimum post-growth rapid thermal annealing temperature for the structural and optical properties of hydrothermal ZnO Nanorods

In this study, Zinc oxide nanorods has been inspected under wide range of rapid thermal annealing temperatures to explore the optimum post growth annealing temperature, required for particular applications, under structural, electrical and optical properties. Vertical ZnO Nanorods has been grown via low temperature hydrothermal route on Silicon substrate, then the as-grown NRs were undergone through rapid thermal annealing process in nitrogen environment. The rapid thermal annealing temperature ranges from 300°C to 900°C. Full-width-half-maxima data, from X-ray diffraction peaks reveals that better crystallinity is achieved at 600°C. Scanning electron microscopy tells about the uniformity of the diameter of nanorods in the same range. Photoluminescence spectra gives strong emission at higher temperature with the peak emission at 380nm wavelength, which confirms the wider direct bandgap of ZnO. Moreover, various aspects of ZnO nanorods have been thoroughly investigated under different annealing temperature, which can be helpful in choosing a specific annealing temperature for certain kind of applications.