Investigation of growth parameter influence on hydrothermally grown ZnO nanowires using a research grade microwave

Abstract

ZnO nanowires (NWs) were grown using a research grade microwave with integrated temperature control via a hydrothermal method on a ZnO seed layer.The influences of growth time, temperature, precursor concentration and ratio, and seed layer structure on resulting NW morphology were studied using scanning electron microscopy (SEM) and x-ray diffraction (XRD). The seed layer was found to have the largest influence on NW growth. When anneals were included as part of the surface treatment prior to growth, increased crystallinity of the seed layer led to larger diameter wires. For high temperature anneals (900°C), an additional peak appeared in XRD data, which is believed to be CORRESPONDING to Zn 2 SiO 4 which WAS forming at the interface between the ZnO seed layer and the Si wafer. With good process control, it was possible to grow a uniform, vertically oriented array of NWs. With a 1:1 nutrient solution of 25 mM Zn(NO 3 ) 2 and 25 mM hexamethylene tetramine (HMT), a growth 2 temperature of 85 °C, and a growth time of 60 minutes, NWs with a length of 696 nm with ± 7% across the sample was achieved.