Growth And Photoluminescence Property Study Of ZnO Nanostructures Grown By Laser Ablation CVD

Due to special physical and chemical properties, a lot of researchers pay attention to ZnOnanomaterial. At the same time, with the continuous research improvement of growth theoryand equipments manufacture, the gas phase growth method based on laser-matter interactionto grow semiconductor nanostructures has been further developed. In this paper, laser ablationchemical vapor deposition （LACVD） and pulsed laser deposition （PLD） method were adoptedto study the influence of different experimental parameters on the growth of ZnOnanostructure. The grwoth mechnism and corresponding photoluminescence properties wereemphasised for different ZnO nanostructures. The content and results are as follows.1. The thickness of gold catalyst and substrate temperature are the most important factorsfor unifirm ZnO nanorod growth with LACVD. When the thickness of catalyst was2nm andtemperature was925℃, ZnO nanorods of （002） preferential growth orientation and uniformdiameter were grown on single-crystal silicon substrate. Due to the dynamic wettabilitybetween the substrate and the gold film, continuous gold film will change to isolated particleswith increasing temperature. The size of gold particle therefore affects the diameter of ZnOnanorods. The LACVD growth mechenism of ZnO nanorods can be described with acombined VLS and VS process. The incorporation of magnesium increases the growth rate ofthe non-polar Zn_xMg_1-xO crysta faces and induces the formation of Zn_1-xMg_xO nanobelts witha bigger bandgap. At the same time, more defect-related levels were measered with PLspectrum in the forbidden gap.2. The optimum PLD growth condition of ZnO films deposited on three types ofsubstrates was investigated. When ZnO thin films were grown on sapphire substrates, novelZnO nanobridge structure was grown by only target rotation. More unifirm ZnO films can begrown by a in situ two-step growth method. Growth pressure is an important factor thatdetermines the roughness of the film surface when ZnO film gorwn on silicon or FTO galsssubstrates. High temperature can increase the migration ability of the particles on the substratesurface and thus a more uniform and flat film will be obtained.3. Large-area, high-quality ZnO and ZnMgO nanowalls were grown on sapphiresubstrate without catalyst assisted using LACVD. We systematically study the influence of the growth parameters of pressure, temperature, target distance on the morphology andstructure of Zn_1-xMg_xO nanorods and nanowalls. Zn_1-xMg_xO nanostructures controlled growthwas realized by optimizing the growth pressure and target-substrate distance. Due to the highgrowth pressure, the transfer rate of Mg component in the target material by LACVD methodis smaller than that of traditional low-pressure PLD method.