Study On The Growth Mechanism And Preparation Of ZnO Crystal

Zinc oxide crystal as a new generation of wide-band, multi-functional direct band-gapⅡB-ⅥA semiconductor material, has excellent optoelectronic, conductivity, piezoelectric, gas sensing, pressure-sensitive features and et al. The band-gap of ZnO semiconductor is 3.37 eV at room temperature, and the Binding Energy of Exciton can be as high as 60 MeV. ZnO which compared to UV semiconductor optoelectronic devices has great potential value. Difficulty of preparation and attractive application make ZnO being the focus of materials research. By heating temperature, insulation temperature and insulation time of ZnO are analyzed and reserached with the help of XRD and SEM, in reaction process.The influence that the ZnO crystal growth by different of heating temperature, insulation time and insulation temperature using gas transmission with Zn and air in this paper.The results show that the heating temperature of 300~500℃, which ZnO whisker is the main morphology in low temperature, while spot adjunct of ZnO in high temperature; insulation temperature of 1000~1300℃, which different insulation environment effects the growth of ZnO; and insulation time for 24~40 hours, which ZnO crystal is larger of size as the longer insulation temperature by gas phase method. Finally we prepared diameter of 0.8 mm and length of 2.4 mm crystal of ZnO. Ultimately the ZnO controllable growth was realized.It shows that the sample was all of ZnO from XRD photograph. The diffraction peaks which are shape and narrow show its crystallization well. The XRD pattern is similar with JCPDS cards, 36-1451, shows that the structure of ZnO is hexagonal wurtzite with lattice constant a = 0.32568nm, c = 0.52154nm.It shows that the crystal was columnar from the SEM photographs of large-size ZnO crystals and indicates that the crystal grows along different direction, but the +c-axis of ZnO is the main direction. The results show that the gas phase method is feasible.This method is of great advantages in simple process, high punity and less impunity.