Figure 5.

Top: Schematic illustration depicted the two steps of growth based on self-assembly from primary particles to a tribulus-shaped crystal.aTEM image showing attachment of new particles to elongate the branches (arrowheads in the section A, B and C);bHRTEM image of section B in (a) indicating the connecting region (between arrowheads) between a new particle and the arm;chigh-resolution TEM image of a tribulus-shaped nanoparticle;dmagnification of the section A in (c) exhibiting three random arrangement particles A1, A2, A3 and two oriented attachment branches A4 (<11-20> direction) and A5 (<0001> direction)

Hu et al. Nanoscale Research Letters 2009 4:437-443   doi:10.1007/s11671-009-9265-2