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Issue 28, 2011
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Strategies for controlling Si nanowire formation during Au-assisted electroless etching

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Abstract

Dramatic changes in the morphologies of Si nanowires (NWs) ranging from vertical, to hooked, to ground-collapsed shapes are presented depending on the HF/H2O2 ratio in the etch solution during Au-assisted electroless etching. It is shown that the deviations from vertical NWs are not due to capillary action but correlated with the development of nanoporous structures, which is attributed to excess hole (h+) diffusion toward the NWs' sidewalls during the etching process. The role of hole diffusion is made more evident by observation of NWs with the neck formation when transitioning to different etching regimes during SiNW formation. Furthermore, the hooked and ground-collapsed SiNW can be suppressed at the cost of enhanced tapering by adding a strong electrolyte in solution, which is correlated to reduced etching rate resulting from electric screening of the charged Au surfaces. We provide an important finding that common salts such as NaCl, KCl, and CaCl2 can be useful retardants for the metal-assisted electroless etching. The new insights into structural transformation presented in this study afford greater control over the structure of SiNWs produced by metal-assisted electroless etching.

Graphical abstract: Strategies for controlling Si nanowire formation during Au-assisted electroless etching

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Publication details

The article was received on 18 Mar 2011, accepted on 27 Apr 2011 and first published on 06 Jun 2011


Article type: Paper
DOI: 10.1039/C1JM11164G
Citation: J. Mater. Chem., 2011,21, 10359-10363
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    Strategies for controlling Si nanowire formation during Au-assisted electroless etching

    D. H. Lee, Y. Kim, G. S. Doerk, I. Laboriante and R. Maboudian, J. Mater. Chem., 2011, 21, 10359
    DOI: 10.1039/C1JM11164G

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