The definition or concept of the nanostructure has two levels of implication [1].The first refers to nanostructures,including nanoparticles,nanoclusters,nanotubes,nanorods,nanowires and nanopores,which have at least one dimension in the size range of approximately 1 to 100 nm.The second refers to the unique properties of nanostructures.When their size is reduced to sub-micron or especially to nanometer scale,their properties are significantly altered.Obviously,the latter implication is more meaningful and suggests numerous potential applications [2].Relevant studies have led to a broad spectrum of innovative developments in various areas,including physics,chemistry,medicine,energy,and sensing.