本文分别用三甲基镓和高纯蓝氨作为Ga源和N源,Ni(NO3)2作为催化剂,在Si(111)衬底上制得针尖状GaN纳米棒。测试结果表明制备的CaN纳米棒是沿〈100〉方向生长的纯六方相结构。通过对生长过程的分析,我们认为GaN纳米棒的生长过程不仅受到VIS机制的控制,而是多种生长方式共同作用的结果。在反应的初期,GaN纳米棒的生长遵从VIS机制;但是随着CaN纳米棒轴向和径向的生长,GaN纳米结构中纳米棒端部的Ni催化剂纳米球会被“挤”出顶部,在较大的气流流速下被吹落至衬底上,失去催化剂诱导作用的纳米棒随后自行外延生长;而吹落至衬底上的Ni催化剂纳米球成为第二次生长有利的形核位置,且再次生长出粗短的纳米棒。因此不同生长机制得到的GaN纳米棒交织在一起,形成了最终的GaN纳米结构。
GaN nanorods were grown by metal organic chemical vapor deposition (MOCVD) with Ni(NO3)2 as the catalyst precursor and trimethyl gallium and high purity blue ammonia as the Ga and N sources, respectively, on Si(111) substrates. The mierostructures of the Gain nanorods were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the (100) oriented GaN nanorod has a hexagonal crystal structure. We suggest that three mechanisms, including the vapor liquid solid growth, catalyst growth and the (111 ) preferential growth orientation, account for the GaN nanorod formation.