Research On CVD Growth Of GaN Nanowires

Semiconductor nanowires are praised as building blocks for next generation of micro-nano electronic devices. GaN is an ideal material for short-wave light-emitting devices and high frequency and high power electronic devices due to many advantages, such as wide band gap, high electron mobility, high thermal conductivity. Therefore, the growth of GaN nanowires is extensively studied.In this paper, based on vapor-liquid-solid (VLS) mechanism, GaN nanowires grown on Si substrate were studied by CVD method. The main results are briefly summarized as follows:(1) The growth of GaN nanowires were studied with Ni as catalyst by using metal Ga and Ga/GaCl3as sources, respectively. The experimental results show that high density and straight GaN nanowires with high quality are synthesized on by using Ga/GaCl3sources. The growth of GaN nanowires by using Ga/GaCl3sources is proposed by this paper for the first time.(2) The growth of GaN nanowires were studied with Au as catalyst by using metal Ga, Ga2O3and the mixture of Ga2O3and Ga as sources, respectively. It is found that the nanowires grown by using Ga2O3and the mixture of Ga2O3and Ga as sources are zigzag and the nanowires grown by using metal Ga as source are straight. The growth mechanism of nanowires with Au as catalyst is VLS mechanism.(3) The growth of GaN nanowires were studied by using Au/Ni as catalyst. It is found that Au/Ni can avoid Au diffusion into Si substrate, so the uniform nanoparticles distributed on Si substrate are obtained. Compared with the Au catalyst, Au/Ni catalyst trend to obtain high quality nanowires.(4) This paper designed two kinds of chambers for metal organic chemical vapor deposition (MOCVD). The advantage and disadvantage of each chamber are compared by nanowire growth experiments. It is found that with decreasing pressure of chamber, lateral growth of nanowire is enhanced.