Figure 3.

FESEM images of products obtained by the surfactant-assisted in situ chemical etching strategy using different etching time a 0 h, b 0.5 h, c 1 h, and d 1.5 h

Wang et al. Nanoscale Research Letters 2010 5:1102-1106   doi:10.1007/s11671-010-9608-z