Published online by Cambridge University Press: 31 January 2011
In this study, well separated tapered CuO nanowires have been synthesized on copper grid using an easy and cost effective thermal oxidation method. A set of spectroscopic investigations have been performed on one single tapered CuO nanowire using Energy Dispersive X-ray, confocal Raman and confocal Photoluminescence spectroscopy to get insight into the mechanism of growth of the nanowires. Energy Dispersive X-ray studies reveal crystallization process of CuO nanowires occur from Cu/Cu2O mixed phase state to pure CuO structure. Raman measurements indicate a little sharpening of the Raman peaks with increasing growth temperature of the nanowires starting from 400°C to 600°C. Photoluminescence studies were carried out by mapping along the length of the nanowire to investigate the growth as well as optical properties of a single tapered CuO nanowire. As the diameter of the single tapered CuO nanowire decreases, the green emission of the nanowire gradually shifts towards the higher energy side. A steady blue shift of 20 nm of the photoluminescence peak has been attributed to the nanosize effect of the tapered nanowire along the length and enhanced surface defects.