基片表面朝向对ZnO纳米线生长机理的影响

Effect of the Exposure of Substrate on the Growth Mechanism of ZnO Nanowires

采用热蒸发ZnO粉末法,以金膜为催化剂,在两片表面分别朝上和朝下的Si(100)基片上生长ZnO纳米线(样品分别标为1#和2#)。X射线衍射(XRD)图谱上只存在ZnO的(002)衍射峰,说明ZnO纳米线沿(001)择优取向。通过扫描电子显微镜(SEM)表征发现,ZnO纳米线整齐排列在Si基片上,直径在100nm左右,平均长度为4μm。通过分析得出,两种基片上生长的ZnO纳米线的生长机理是不相同的:1#样品,在基片表面上先生长ZnO薄膜,再在薄膜上生长ZnO纳米线;2#样品,ZnO纳米线直接外延生长在基片表面。结果显示基片表面的朝向影响ZnO纳米线的生长机理。

ZnO nanowires were prepared on two piece of Si （100） substrates which faced up and down separately using Au as catalyzer by thermal evaporation and vapor transport. Only （002） diffraction peaks of ZnO can be found on the X-ray diffraction （XRD） patterns, this indicates that ZnO nanowires exhibit （001） preferred orientation. The scanning electronic microscope （SEM） images show that the average diameter is 100 nm and the average length is 4 μm. They are aligned on Si substrate well. While substrates facing up, the ZnO thin film of thickness of 500 nm is deposited on Si substrate firstly and ZnO nanowires grow on the ZnO thin films. And while substrates facing down, epitaxial ZnO nanowires grow on the substrates. The result indicates that the exposure of substrate affects the growth mechanism of ZnO nanowires.