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Preferential Positioning of Dopants and Co-Dopants in Embedded and Freestanding Si Nanocrystals
journal contribution
posted on 2014-03-19, 00:00 authored by Roberto Guerra, Stefano OssiciniIn
this work we aim at understanding the effect of n- and p-type
substitutional doping in the case of matrix-embedded and freestanding
Si nanocrystals. By means of ab initio calculations
we identify the preferential positioning of the dopants and its effect
on the structural properties with respect to the undoped case. Subsequently,
we consider the case of phosphorus and boron co-doped nanocrystals
showing that, against the single-doping situation, the energetics
strongly favors the binding of the impurities at the nanocrystal surface.
Indeed we demonstrate that the polar B–P bond forms a stable
permanent electric dipole that radially points inward in the nanocrystal.
Such a noteworthy characteristic and its physical consequences are
discussed alongside new potential applications.