Formation mechanism of SiGe nanorod arrays by combining nanosphere lithography and Au-assisted chemical etching
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
Nanoscale Research Letters 2012, 7:140 doi:10.1186/1556-276X-7-140Published: 18 February 2012
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.