Gas Flow Rate Effects on Structural Properties of Zinc Oxide Nano-Wires Grownup on GaAs(002) Substrate Using Vapour-Solid Mechanism

In this paper, ZnO nano-wires were grown on gallium arsenide (GaAs) substrates using a simple thermal evaporation technique without a catalyst. At a fixed evaporation temperature and growth time, we varied the Ar and O2 gas flow rates from 100 to 300 sccm. We characterized the obtained nano-wires using a field effect scanning electron microscope (equipped with an energy dispersive X-ray analysis), as well as X-ray diffraction and Raman spectroscopy. Scanning electron micrographs revealed that ZnO nano-wires exhibited varying diameters depending on the gas flow rate. Energy-dispersive X-ray analysis revealed the elemental compositions of the samples and confirmed the presence of Zn and O2. X-ray diffraction and Raman analysis confirm that the as-grown ZnO nanostructures are of hexagonal wurtzite structure, with good crystal quality, and grow along the c-axis. The growth mechanism has been discussed.