Shape-Control of ZnTe Nanocrystal Growth in Organic Solution

Precursor-reduction method is employed to synthesize nanometer-sized ZnTe. Zinc blende ZnTe nanocrystals growth in three different shapes under various conditions, that is, quasi-spheres, tetrahedrons, and nanorods, have been observed. It is believed that the crystal growth of ZnTe is the rate-controlling step when superhydride was employed at 250 °C, resulting in quasi-spherical ZnTe nanocrystals. Replacement of superhydride with oleylamine alters the precursor-reduction step as the rate-controlling step, giving tetrahedral ZnTe nanocrystals. At low temperature (150 °C) and in the presence of superhydride and oleylamine, kinetic growth and/or surfactant-template dominate the process, causing an anisotropic crystal growth into ZnTe nanorods. ZnTe nanocrystals are typically surface-active with a similar crystal structure of CdSe. The present study provides a clue to understand the zinc blende-type nanocrystal growth mechanism in high-temperature colloidal system, and may lighten certain strategies of future nanomaterials processing, for example, the synthesis of one-dimensional zinc blende-type semiconductors in solution phase.