Lee Chan-Yang, Kim Gil-Sung, Lee Seung-Yong, Kim Tae-Hong, Seo Deok-Won, Lee Sang-Kwon
Department of Semiconductor Science and Technology, Basic Research Laboratory (BRL), Semiconductor Physics Research Center (SPRC), Chonbuk National University, Jeonju 561-756, Korea.
J Nanosci Nanotechnol. 2011 Aug;11(8):6946-52. doi: 10.1166/jnn.2011.4244.
Single crystalline silicon nanowires (SiNWs) were grown on Si(100) substrate using a gold (Au)-catalyzed vapor-liquid-solid (VLS) approach. The dependence of the growth time (i.e., the time of exposure to the Si source) on the density and surface evolution of the grown SiNWs is considered. It was observed that the density of grown SiNWs on Si substrate increased with increasing growth time. The highest density (approximately 1.1 x 10(6) mm(-2)) was reached at 4 hr. Upon further exposure to the Si source, we observed that the density was maintained for up to 9 hr. We suggest that the increased Si chemical potential in Au-Si droplets with increased growth time enhanced the SiNW growth rate at the interfaces between Au-Si droplets and SiNWs, and enhanced the transition of the NWs from the existing Au-Si droplets onto Si substrate. This allows the SiNW density to increase with increased growth time of up to 4 hr. Moreover, we examined the influence of the growth time on surface evolution including Au diffusion, facet and taper formation, and vapor-solid (VS) growth of the SiNWs. To explain the behavior of the grown SiNWs in the VLS process, we propose a combined model using the VLS and VS growth mechanisms.
采用金（Au）催化的气-液-固（VLS）方法在硅（Si）（100）衬底上生长单晶硅纳米线（SiNWs）。研究了生长时间（即暴露于硅源的时间）对生长的SiNWs密度和表面演变的影响。观察到硅衬底上生长的SiNWs密度随生长时间增加而增加。在4小时时达到最高密度（约1.1×10⁶ mm⁻²）。进一步暴露于硅源后，观察到密度在长达9小时内保持不变。我们认为，随着生长时间增加，Au-Si液滴中硅化学势的增加增强了Au-Si液滴与SiNWs界面处的SiNW生长速率，并增强了纳米线从现有的Au-Si液滴向硅衬底的转变。这使得SiNW密度在长达4小时的生长时间内随生长时间增加而增加。此外，我们研究了生长时间对表面演变的影响，包括Au扩散、晶面和锥度形成以及SiNWs的气-固（VS）生长。为了解释VLS过程中生长的SiNWs的行为，我们提出了一个结合VLS和VS生长机制的组合模型。
