The synthesis of zinc oxide(ZnO) nanowires is achieved by vapor phase transportation(VPT) method.The designed quartz tube,whose both ends are narrow and the middle is wider,is used to control the growth of ZnO nanowires.Dielectrophoresis(DEP) method is employed to align and manipulate ZnO nanowires which are ultrasonic dispersed and suspended in ethanol solution.Under the dielectrophoretic force,the nanowires are trapped on the pre-patterned electrodes,and further aligned along the electric field and bridge the electrode gap.The dependence of the alignment yield on the applied voltage and frequency is investigated.
A simple method is adopted to grow ZnO nanofibers laterally among the patterned seeds designed in advance on silicon substrate.The preparation of seed lattices is carried out by lithographing the metal zinc film evaporated on the substrate.A layer of aluminum is covered on the zinc layer to prevent the ZnO nanorods vertically growing on the top surface.After oxidation,the patterned ZnO/Al2O3 spots are formed at the sites for the horizontal growth of ZnO nanofibers by the vapor phase transportation(VPT) method using the zinc powders as source material.
纳米结构的氧化锌兼备了宽直接带隙(Eg=3.34 eV)、强激子束缚能(60 m eV)的优良特性,同时又具备了纳米材料独特的微结构与光电功能,可望成为高效率紫外发光二极管以及低阈值紫外半导体激光器的良好材料。以我们的工作为基础,利用不同结构的ZnO作增益介质,概述了低维ZnO纳米材料中的自发辐射与受激辐射过程,观察到了放大的自发辐射(ASE)与受激振荡现象,并讨论了自发辐射、ASE及受激辐射的产生机制。
