Figure 3

SEM micrographs of the SiNWs after different chemical treatments. Cross-sectional SEM images of SiNWs formed at 20-min etching time, after different chemical treatments. In (a) the nanowires after an HF dip are depicted. The as-formed nanowires are depicted in the micrograph in the inset of (a). The nanowires after successive. In (b) and (c) the nanowires after successive HF/piranha (b) and HF/piranha/HF (c) treatments are shown. After the last treatment, the nanowires were almost fully destroyed.