First-principles Theoretical Analysis of Transition-metal Doping of ZnSe Quantum Dots

Singh, T. and Mountziaris, T. J. and Maroudas, D.. (2012) First-principles Theoretical Analysis of Transition-metal Doping of ZnSe Quantum Dots. Journal of Applied Physics, 112 (2).

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We present a systematic analysis of the underlying mechanism of transition-metal doping in ZnSe nanocrystals, using first-principles density functional theory calculations. Our analysis focuses on the adsorption and surface segregation of Mn dopants on ZnSe nanocrystal surface facets. We find that the chemical potentials of the growth precursor species determine the surface structure and morphology of the nanocrystals. We report binding energies for Mn adsorption onto ZnSe surfaces and find that all the anion-rich surfaces contribute toward dopant adsorption onto ZnSe nanocrystal surface facets. Beyond a critical value of dopant surface coverage, these adsorbed dopants may induce structural transitions in low-Miller-index surface facets, resulting in morphological transitions of the ZnSe nanocrystals. In addition, the dopant binding-energy dependence on the dopant surface concentration explains the doping difficulties during nanocrystal growth. Finally, we report surface segregation energy profiles for Mn dopant segregation on low-Miller-index ZnSe nanocrystal surface facets. We find that, under conditions that render ZnSe(001)-(2 x 1) as the dominant dopable surface of ZnSe nanocrystals, Mn dopants do not have a tendency to segregate on this surface; this guarantees that the dopants remain incorporated into the core regions of the nanocrystal instead of escaping to the surface. (C) 2012 American Institute of Physics.

Item Type: Article
Additional Information: Singh, Tejinder Mountziaris, T. J. Maroudas, Dimitrios
Collections: Nanomanufacturing Research Collection > Nanomanufacturing Nanoscale Science and Engineering Centers > Center for Hierarchical Manufacturing
Depositing User: Robert Stevens
Date Deposited: 26 Mar 2014
Last Modified: 26 Mar 2014 19:43

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