Morphology and crystal quality investigation of hydrothermally synthesized ZnO micro-rods

Micro-structural and room and low temperature photoluminescence response of undoped one-dimensional ZnO were investigated. ZnO rods of different morphology and size were synthesized by controlling growth parameters through hydrothermal technique. The phase and microstructure analysis were carried out by X-ray diffraction and scanning electron microscopy. The room and low temperature photoluminescence spectra of the samples were studied. Near band edge sharp exciton emission peaks and broad defect-related peaks were observed. The ratio of band edge emission to deep level emission was controlled by tuning the initial concentration, pH and reaction time period. Optimal growth condition for growth of micro-rods with improved crystal quality was obtained with initial Zn²⁺ concentration of 0.5 M, at reaction temperature of 120 °C, pH of 9.9 and in a reaction time period of 6 h.