Transition-Metal Doping Of Small Cadmium Selenide Clusters

Using first-principles density functional theory calculations, we investigate the mechanism of Mn doping of colloidal CdSe nanocrystals. We find that Mn dopants have high binding energies for adsorption onto the sites of small CdSe clusters (with diameters d < 2 nm) as compared to those for adsorption onto the most stable surface facets of larger CdSe nanocrystals (d >= 5 nm) with wurtzite lattice structure. These high binding energies, in conjunction with the characteristics of Mn surface segregation on CdSe nanocrystal surface facets, explain experimental reports of high doping efficiency for small-size CdSe clusters. (C) 2012 American Institute of Physics. [doi:10.1063/1.3680254]