Mechanisms of size-dependent shape evolution of one-dimensional nanostructure growth

The size-dependent morphological evolution of one-dimensional (1D) SnO2 nanostructures has been observed in experiment. It was found that the shape formations of nanowire and nanobelt of SnO2 are size dependent, i.e., the wire is favorable when the size is less than 90 nm and the belt is favorable when the size more than 90 nm, respectively, indicating that a critical size exists in the growth of SnO2 nanostructures to determine their morphologies. The nucleation thermodynamics, growth kinetics, and morphological transition thermodynamics were established to elucidate the size-dependent morphological evolution. The theoretical predictions are consistent with experiments, suggesting that the thermodynamic driving force seems to be the physical origin of the shape evolution.