Kim Ilsoo, Lee Ki-Young, Kim Ungkil, Park Yong-Hee, Park Tae-Eon, Choi Heon-Jin
Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749 Korea.
Nanoscale Res Lett. 2010 Jun 17;5(10):1535-1539. doi: 10.1007/s11671-010-9673-3.
We report on bifurcate reactions on the surface of well-aligned Si(1-x)Ge(x) nanowires that enable fabrication of two different coaxial heterostructure nanowires. The Si(1-x)Ge(x) nanowires were grown in a chemical vapor transport process using SiCl(4) gas and Ge powder as a source. After the growth of nanowires, SiCl(4) flow was terminated while O(2) gas flow was introduced under vacuum. On the surface of nanowires was deposited Ge by the vapor from the Ge powder or oxidized into SiO(2) by the O(2) gas. The transition from deposition to oxidation occurred abruptly at 2 torr of O(2) pressure without any intermediate region and enables selectively fabricated Ge/Si(1-x)Ge(x) or SiO(2)/Si(1-x)Ge(x) coaxial heterostructure nanowires. The rate of deposition and oxidation was dominated by interfacial reaction and diffusion of oxygen through the oxide layer, respectively.
我们报道了在排列良好的Si(1-x)Ge(x)纳米线表面发生的分叉反应，这些反应能够制造出两种不同的同轴异质结构纳米线。Si(1-x)Ge(x)纳米线是在化学气相传输过程中，以SiCl(4)气体和Ge粉为源生长而成的。纳米线生长后，终止SiCl(4)气流，同时在真空下引入O(2)气流。纳米线表面的Ge由Ge粉的蒸汽沉积而成，或者被O(2)气体氧化成SiO(2)。在2托的O(2)压力下，从沉积到氧化的转变突然发生，没有任何中间区域，并且能够选择性地制造出Ge/Si(1-x)Ge(x)或SiO(2)/Si(1-x)Ge(x)同轴异质结构纳米线。沉积速率和氧化速率分别由界面反应和氧通过氧化层的扩散主导。
