Synthesis and characterization of Au-ZnO nanorods growth by CVD method

On silicon (100) surface substrates, single-crystal ZnO nanorods (NRs) were produced in a CVD (Chemical vabour deposition) home-made reactor with the help of a catalytic Au-seeds layer. Si substrates were coated with an Au- catalyst layer of 20 nm thickness using direct current sputtering (DC sputtering). Au-catalyst layer plays a pivotal role in synthesizing nanostructures by VLS (Vapour-Liquid-Solid) process. Zinc powder [0.2 g] was used as a source, and silicon (100) of 1.0 x 1.0 cm(2) area was used as a substrate. We utilized a mixture of argon/oxygen gases (40/10 flow rate) with 700 & DEG;C growth temperature for 1 h to ZnO NRs formation. The Au-ZnO NRs were characterized by XRD (X-ray diffraction), AFM (Atomic force microscopy), and FESEM (Field emission scanning electron microscopy) techniques. The results demonstrate that the Au-ZnO NRs are single crystalline and have a hexagonal structure (wurtzite) with a (101) preferred orientation. The sharp and robust diffractions from ZnO NRs confirm that the CVD thermal-grown ZnO NRs have good crystallinity and high purity. The AFM pictures showed that the average particle size of Au-ZnO NRs is 45.31 nm, which is in reasonable agreement with the crystallite sizes estimated from the XRD pattern. The FESEM confirm that the grown ZnO NRs are hexagonal wurtzite NRs. As a whole, Au-ZnO NRs ranged in size from 1.6 to 1.738 & mu;m in length and 250-300 nm in diameter on average. The Au catalyst seed layer acts as a nucleation layer that draws Zn2+ and O ions to the substrate's surface and serves as an active site for the growth of ZnO NRs. Those results were accomplished with discussion of the mechanism and model of growth for Au-ZnO NRs.