Semiconductor nanocrystals (NCs) show a range of properties that are quite different from bulk semiconductors and like the bulk materials, can be tailored by doping with specific impurities. However, experimental efforts show that doping NCs is much harder than doping bulk semiconductors. We are using computer simulations to study the processes that control the doping process of colloidally grown NCs. These include the attachment of surfactant molecules to the NC surface, the reaction of dopant ions with the surfactants, and the incorporation of the dopants into the growing NC. Simulations use a range of techniques, from first principles density functional theory calculations to interatomic potentials and methods that couple these approaches. We can simulate individual attachment, detachment, and reaction processes, as well as the effects of the solvent on the reactions. Using these simulations we can explain observed experimental behavior, for example dependence on the choice of dopant precusors and surfactant molecules, as well as predict effective routes for synthesizing new doped NCs.

 

key words

Colloidal nanocrystal growth; Computer simulations; Density functional theory; Nanocrystal doping; QM/MM; Solvation effects;

Citizenship:  Open to U.S. citizens and permanent residents

Level:  Open to Postdoctoral applicants