Figure 1.

a–e SEM top views (and cross-sections in insets) of samples 1, 2, 3, 4 and 5, respectively; f SEM bottom view (and bottom side view in inset) of sample 1.

Cao et al. Nanoscale Res Lett 2011 6:64   doi:10.1007/s11671-010-9812-x