Figure 3.

Back-scattered electron SEM images of n-type SiNWs (a) before and (b) after acid treatment. The white dots (marked by white arrows) denote the metal catalyst droplets for n-type SiNW VLS growth. After acid treatment, the white dots are almost absent.

Xie et al. Nanoscale Research Letters 2012 7:621   doi:10.1186/1556-276X-7-621
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