Figure 2.

SEM images of ZnO dumbbells (a) and ZnO/ZnS hollow nanocages (b); TEM and HRTEM images of ZnO dumbbells (c, d) and ZnO/ZnS hollow nanocages (e, f)

Yu et al. Nanoscale Research Letters 2010 5:644-648   doi:10.1007/s11671-010-9528-y