Wurtzite or zinc blende? Surface decides the crystal structure of nanocrystals

Abstract

We show for the first time that the stability of the wurtzite or the zinc blende phase for CdE (E = S, Se, Te) nanocrystals strongly depends on the surface of these nanocrystals. Anion rich surfaces prefer to crystallize in the zinc blende structure whereas cation rich surfaces tend to favor the wurtzite phase. Transformations from one phase to the other can be effected by merely changing the surface of the particles and annealing at a specified temperature. Our results show that it is not only important to choose the synthesis temperature and ligands in order to achieve crystallization in a preferred phase but also the surface of the particles is a deciding factor.