Key Laboratory of Semiconductor Material Science, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083, People's Republic of China.
Nanoscale Res Lett. 2011 Jul 21;6(1):463. doi: 10.1186/1556-276X-6-463.
Catalyst-free, vertical array of InAs nanowires (NWs) are grown on Si (111) substrate using MOCVD technique. The as-grown InAs NWs show a zinc-blende crystal structure along a < 111 > direction. It is found that both the density and length of InAs NWs decrease with increasing growth temperatures, while the diameter increases with increasing growth temperature, suggesting that the catalyst-free growth of InAs NWs is governed by the nucleation kinetics. The longitudinal optical and transverse optical (TO) mode of InAs NWs present a phonon frequency slightly lower than those of InAs bulk materials, which are speculated to be caused by the defects in the NWs. A surface optical mode is also observed for the InAs NWs, which shifts to lower wave-numbers when the diameter of NWs is decreased, in agreement with the theory prediction. The carrier concentration is extracted to be 2.25 × 1017 cm-3 from the Raman line shape analysis. A splitting of TO modes is also observed.PACS: 62.23.Hj; 81.07.Gf; 63.22.Gh; 61.46.Km.
使用 MOCVD 技术在 Si（111）衬底上生长无催化剂的垂直砷化铟纳米线（NWs）阵列。生长的 InAs NWs 呈现沿 <111> 方向的闪锌矿晶体结构。研究发现，随着生长温度的升高，InAs NWs 的密度和长度减小，而直径增大，表明无催化剂的 InAs NWs 生长受成核动力学控制。InAs NWs 的纵光学（LO）和横光学（TO）模式的声子频率略低于体材料的声子频率，这被推测是由于 NWs 中的缺陷引起的。还观察到 InAs NWs 的表面光学模式，当 NWs 的直径减小时，表面光学模式向较低的波数移动，这与理论预测一致。通过拉曼谱线形状分析提取出载流子浓度为 2.25×1017cm-3。还观察到 TO 模式的劈裂。PACS：62.23.Hj; 81.07.Gf; 63.22.Gh; 61.46.Km。
