Morber Jenny Ruth, Ding Yong, Haluska Michael Stephan, Li Yang, Liu J Ping, Wang Zhong Lin, Snyder Robert L
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245, USA.
J Phys Chem B. 2006 Nov 2;110(43):21672-9. doi: 10.1021/jp064484i.
We report here a systematic synthesis and characterization of aligned alpha-Fe2O3 (hematite), epsilon-Fe2O3, and Fe3O4 (magnetite) nanorods, nanobelts, and nanowires on alumina substrates using a pulsed laser deposition (PLD) method. The presence of spherical gold catalyst particles at the tips of the nanostructures indicates selective growth via the vapor-liquid-solid (VLS) mechanism. Through a series of experiments, we have produced a primitive "phase diagram" for growing these structures based on several designed pressure and temperature parameters. Transmission electron microscopy (TEM) analysis has shown that the rods, wires, and belts are single-crystalline and grow along <111>m or <110>h directions. X-ray diffraction (XRD) measurements confirm phase and structural analysis. Superconducting quantum interference device (SQUID) measurements show that the iron oxide structures exhibit interesting magnetic behavior, particularly at room temperature. This work is the first known report of magnetite 1D nanostructure growth via the vapor-liquid-solid (VLS) mechanism without using a template, as well as the first known synthesis of long epsilon-Fe2O3 nanobelts and nanowires.
我们在此报告了一种使用脉冲激光沉积（PLD）方法在氧化铝衬底上系统合成并表征排列整齐的α-Fe₂O₃（赤铁矿）、ε-Fe₂O₃和Fe₃O₄（磁铁矿）纳米棒、纳米带和纳米线的过程。纳米结构尖端存在球形金催化剂颗粒，表明通过气-液-固（VLS）机制进行选择性生长。通过一系列实验，我们基于几个设计好的压力和温度参数，绘制了生长这些结构的原始“相图”。透射电子显微镜（TEM）分析表明，这些棒、线和带是单晶的，并且沿<111>m或<110>h方向生长。X射线衍射（XRD）测量证实了相和结构分析。超导量子干涉装置（SQUID）测量表明，氧化铁结构表现出有趣的磁行为，尤其是在室温下。这项工作是首次有关于不使用模板通过气-液-固（VLS）机制生长磁铁矿一维纳米结构的报道，也是首次合成长ε-Fe₂O₃纳米带和纳米线。
