Effect of One-Coordinated Atoms on the Electronic and Optical Properties of ZnSe Clusters.

To understand the influence of one-coordinated Zn and Se atoms on the structures, electronic, and optical properties of ZnSe clusters, we investigate the Zn37Se20 clusters employing first-principles theoretical calculations. The Zn37Se20 cluster, constructed from the InP nanocrystal structure, possesses a Zn21Se20 core and 16 one-coordinated surface atoms. The effect of one-coordinated atoms is studied by adding or removing one-coordinated atoms of the Zn37Se20 cluster. The calculations show that the modifications of one-coordinated atoms change slightly the coordination states and bond lengths of the atoms on the cluster surface. The clusters with the same core structure and different amounts of one-coordinated atoms have similar optical spectra, suggesting the importance of the cluster core structure in their optical properties.