What is the Influence of Heating Rate and Annealing Temperature on the Growth of ZnO Nanowires?

Abstract:

Zinc Oxide (ZnO) nanowires have been investigated for their unique physicochemical properties, leading to their applications in fields such as electronics, photonics and optics. Currently, there are numerous methods for ZnO nanowire production, such as chemical vapour deposition (CVD), laser ablation, vapour-liquid-solid (VLS) etc. However, these methods can be time-consuming and costly for widespread use outside of laboratories. Thus, a comprehensive understanding of ZnO nanowire growth factors is necessary to enable economic, high-yielding and simple production processes to work on an industrial scale, or for those without the latest technology. In this paper, we investigate two of the growth factors — heating rate and temperature — and their effects on ZnO nanowire growth density (nanowires per µm2) and morphology. We hypothesise that an increase in heating rate (°C/min) and temperature (°C) will produce higher nanowire density due to higher kinetics. While an increase in heating rate with a decrease in temperature, or vice versa, will lead to lower ZnO nanowire growth density, but more contrasting morphologies. We will test this through the synthesis of ZnO nanowires using thermal evaporation method with different heating rates and 2-hour annealing temperatures of 400, 500 and 600 degrees celsius.