Open Access Nano Express

Formation mechanism of SiGe nanorod arrays by combining nanosphere lithography and Au-assisted chemical etching

Chih-Chung Lai1, Yun-Ju Lee2, Ping-Hung Yeh2* and Sheng-Wei Lee1*

Author affiliations

1 Institute of Materials Science and Engineering, National Central University, Jhongli, 32001, Taiwan

2 Department of Physics, Tamkang University, Danshui District, New Tapei, 25137, Taiwan

For all author emails, please log on.

Citation and License

Nanoscale Research Letters 2012, 7:140  doi:10.1186/1556-276X-7-140

Published: 18 February 2012

Abstract

The formation mechanism of SiGe nanorod (NR) arrays fabricated by combining nanosphere lithography and Au-assisted chemical etching has been investigated. By precisely controlling the etching rate and time, the lengths of SiGe NRs can be tuned from 300 nm to 1 μm. The morphologies of SiGe NRs were found to change dramatically by varying the etching temperatures. We propose a mechanism involving a locally temperature-sensitive redox reaction to explain this strong temperature dependence of the morphologies of SiGe NRs. At a lower etching temperature, both corrosion reaction and Au-assisted etching process were kinetically impeded, whereas at a higher temperature, Au-assisted anisotropic etching dominated the formation of SiGe NRs. With transmission electron microscopy and scanning electron microscopy analyses, this study provides a beneficial scheme to design and fabricate low-dimensional SiGe-based nanostructures for possible applications.

Keywords:
Ge; nanorod; self-assembly; nanosphere lithography