Table 2.

The classification of nanostructures and typical morphology.

	The Character of Structure	Typical Morphology
0D structure	three dimensions are in the nanoscale	Nanoparticle [7], quantum dot [8], nanocluster [9]
1D structure	two dimensions are in the nanoscale	Nanowire [10], nanofiber [11], nanorod [12], nanotube [13,14]
2D structure	one dimension is in the nanoscale	Nanosheet [15], nanobelt [16], superlattice [17]
3D structure	assembled by one kind or more low dimensional materials	Nanoflowers [18]