MBE法生长ZnO纳米线阵列的结构和光学性能

在氧等离子体辅助的MBE系统中, 以1 nm厚的Au薄膜为催化剂, 基于气?液?固(VLS)机制实现了低温ZnO纳米线阵列在Si(111)衬底表面的生长. 通过场发射扫描电子显微镜(FE-SEM)可以观察到, ZnO纳米线阵列垂直生长在衬底上, 直径为20~30 nm. X射线衍射(XRD)和高分辨透射电镜(HRTEM)结果表明: ZnO纳米线为六方纤锌矿结构, 具有沿c轴方向的择优取向. 光致发光(PL)谱显示在380 nm附近有强烈ZnO本征发射峰, 475~650 nm可见光区域有较强的缺陷导致的发射峰.

Structure and Optical Properties of ZnO Nanowire Arrays Grown by Plasma-assisted Molecular Beam Epitaxy

ZnO nanowire arrays were grown on the Si(111) substrates coated with 1 nm Au catalyst by plasma assisted molecular beam epitaxy(MBE) through Vapor-Liquid-Solid(VLS) growth mechanism at low temperature.Field-emission scanning electron microscope(FE-SEM) reveals that ZnO nanowire arrays grow densely and vertically to the substrate surface with the average diameter of 20 30 nm.The structure properties of ZnO nanowires are measured by X-ray diffraction(XRD) and high resolution transmission electron microscope(HRTEM),the results clearly show that the ZnO nanowire exhibits a typical wurtzite structure with c-axis(002) preferred orientation and good crystal quality.The diffraction peaks can be indexed to a hexagonal structure of bulk ZnO with cell constants of a = 0.325 nm and c = 0.521 nm.The spacing of the lattice fringes along the c axis of the ZnO nanowire is 0.52 nm.The room temperature photoluminescence(PL) spectrum shows that the ZnO nanowire arrays possess good photoluminscent properties with strong near band edge excitonic UV emission around 380 nm and weak defect-related emission in the visible region of 475 650 nm.