采用 Al 催化的气-液-固生长法制备 Si 纳米线及其电学性能。

Fabrication and electrical properties of si nanowires synthesized by Al catalyzed vapor-liquid-solid growth.

机构信息

Department of Materials Science and Engineering, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.

出版信息

Nano Lett. 2009 Dec;9(12):4494-9. doi: 10.1021/nl902808r.

DOI:10.1021/nl902808r

PMID:19904918

Abstract

The synthesis of epitaxially oriented Si nanowires at high growth rates (>1 microm/min) was demonstrated on (111) Si substrates using Al as the catalyst. The use of high H(2) and SiH(4) partial pressures was found to be effective at reducing problems associated with Al oxidation and nanowire nucleation, enabling growth of high aspect ratio structures at temperatures ranging from 500 to 600 degrees C with minimal tapering of the diameter. Because of the high growth rate observed, the Al catalyst is believed to be in the liquid state during the growth. Four-point resistance measurements and back-gated current-voltage measurements indicate that the wires are p-type with an average resistivity of 0.01 +/- 0.004 Omega-cm. These results suggest that Al is incorporated into the Si nanowires under these conditions at concentrations higher than the solubility limit (5-6 x 10(18) cm(-3)) for Al in Si at 550 degrees C. This work demonstrates that Al can serve as both an effective catalyst and p-type dopant for the growth of Si nanowires.

摘要

采用 Al 作为催化剂，在（111）Si 衬底上成功地以高生长速率（>1 微米/分钟）合成了具有外延取向的 Si 纳米线。研究发现，采用高 H2 和 SiH4 分压对于减少与 Al 氧化和纳米线成核相关的问题非常有效，从而能够在 500 至 600°C 的温度范围内生长高纵横比结构，并且直径的锥度最小。由于观察到的高生长速率，据信 Al 催化剂在生长过程中处于液态。四点电阻测量和背栅电流-电压测量表明，这些纳米线是 p 型的，平均电阻率为 0.01±0.004 Ω·cm。这些结果表明，在这种条件下，Al 以高于 Si 中 Al 在 550°C 时的溶解度极限（5-6×1018cm-3）的浓度掺入 Si 纳米线中。这项工作证明了 Al 可以同时作为 Si 纳米线生长的有效催化剂和 p 型掺杂剂。