Morphological diversity and alternate evolution in tin-assisted vapor-transport-grown ZnO micro-nanocrystal tetrapods

Abstract

The authors report the systematic shape-controlled synthesis of wurtzite-type tetrapod-like ZnO (T-ZnO) micro-nanocrystals (μNCs) using a tin-assisted vapor-phase transport (VPT) method. A morphological rebound in the VPT-grown T-ZnO μNCs was first observed at the narrow substrate temperature (T_s) window, 710 °C < T_s < 730 °C, which is found to be sensitive to a hidden local temperature gradient (∇T) distribution of the furnace. Except the well-known experimental factors (e.g., T_s and oxygen partial pressure), our studies demonstrate that the most-neglected environmental temperature (T_E) should be considered in understanding of the morphology uncertainty in the VPT-grown nanostructures, thus potentially offering an insight into the VPT-grown T-ZnO μNCs.