Yang Bing, Yuan Fang, Liu Qingyun, Huang Nan, Qiu Jianhang, Staedler Thorsten, Liu Baodan, Jiang Xin
Shenyang National Laboratory for Materials Science, Institute of Metal Research (IMR), Chinese Academy of Sciences (CAS) , No. 72 Wenhua Road, Shenyang 110016, China.
ACS Appl Mater Interfaces. 2015 Feb 4;7(4):2790-6. doi: 10.1021/am5079896. Epub 2015 Jan 22.
GaN nanowires with homoepitaxial decorated GaN nanoparticles on their surface along the radial direction have been synthesized by means of a chemical vapor deposition method. The growth of GaN nanowires is catalyzed by Au particles via the vapor-liquid-solid (VLS) mechanism. Screw dislocations are generated along the radial direction of the nanowires under slight Zn doping. In contrast to the metal-catalyst-assisted VLS growth, GaN nanoparticles are found to prefer to nucleate and grow at these dislocation sites. High-resolution transmission electron microscopy (HRTEM) analysis demonstrates that the GaN nanoparticles possess two types of epitaxial orientation with respect to the corresponding GaN nanowire: (I) [1̅21̅0]np//[1̅21̅0]nw, (0001)np//(0001)nw; (II) [1̅21̅3]np//[12̅10]nw, (101̅0)np//(101̅0)nw. An increased Ga signal in the energy-dispersive spectroscopy (EDS) profile lines of the nanowires suggests GaN nanoparticle growth at the edge surface of the wires. All the crystallographic results confirm the importance of the dislocations with respect to the homoepitaxial growth of the GaN nanoparticles. Here, screw dislocations situated on the (0001) plane provide the self-step source to enable nucleation of the GaN nanoparticles.
通过化学气相沉积法合成了表面沿径向方向有同质外延修饰的GaN纳米颗粒的GaN纳米线。GaN纳米线的生长是通过金颗粒经由气-液-固(VLS)机制催化的。在轻微锌掺杂下,纳米线沿径向产生螺旋位错。与金属催化剂辅助的VLS生长相反,发现GaN纳米颗粒倾向于在这些位错位置形核并生长。高分辨率透射电子显微镜(HRTEM)分析表明,GaN纳米颗粒相对于相应的GaN纳米线具有两种外延取向:(I)[1̅21̅0]np//[1̅21̅0]nw,(0001)np//(0001)nw;(II)[1̅21̅3]np//[12̅10]nw,(101̅0)np//(101̅0)nw。纳米线能量色散谱(EDS)轮廓线中Ga信号的增加表明GaN纳米颗粒在纳米线边缘表面生长。所有晶体学结果证实了位错对于GaN纳米颗粒同质外延生长的重要性。在此,位于(0001)面上的螺旋位错提供了自台阶源,以实现GaN纳米颗粒的形核。