Substrate free Defect-rich one dimensional ZnO nanostructures

Abstract

One dimensional (1-D) nanostructures of ZnO have been grown using modified ultrasonic-assisted hydrothermal method at low temperature (95οC) in order to investigate its structural, optical and photoluminescence properties. Zinc nitrate and HMT acts as a source of zinc ions (Zn2+) and hydroxide ions (OH−) respectively for the growth of ZnO nanostructures. 1-D ZnO nanostructures consist of well-defined hexagonal shaped nanoscale rods and tubes-like morphologies. The X-ray diffraction pattern confirms the formation of hexagonal wurtzite phase of ZnO with good crystallinity. The crystallite size corresponding to major peaks lies between 39 and 44 nm. The crystallinity corresponding to (0 0 2) plane is found to be 2.061. The optical band gap is found to be 3.42 eV. Room temperature photoluminescence spectrum of 1-D ZnO nanostructures revealed the existence of high concentration of defect emissions i.e. violet, blue-green, green and yellow emissions.