The impurity screening in silicon nanocrystals is analyzed using a first-principles approach based on density functional theory. The electron density induced by a positively charged impurity is evaluated as a function of the nanocrystal size. From our calculations we found that the impurity is responsible for anelectron density accumulation around the impurity site, fully compensated by a positive charge accumulation at the surface(electron depletion). The results are sound and shed new light on the most recent findings in this field. On the basis of the present first-principles results, we propose a Thomas–Fermi model of the impurity screening in silicon nanocrystals. The model gives reliableestimations of the screening function, that well compares to recent ab-initio calculations.
Impurity screening in silicon nanocrystals / F., Trani; D., Ninno; G., Cantele; Degoli, Elena; Ossicini, Stefano. - In: PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES. - ISSN 1386-9477. - STAMPA. - 41:6(2009), pp. 966-968. [10.1016/j.physe.2008.08.028]
Impurity screening in silicon nanocrystals
DEGOLI, Elena;OSSICINI, Stefano
2009
Abstract
The impurity screening in silicon nanocrystals is analyzed using a first-principles approach based on density functional theory. The electron density induced by a positively charged impurity is evaluated as a function of the nanocrystal size. From our calculations we found that the impurity is responsible for anelectron density accumulation around the impurity site, fully compensated by a positive charge accumulation at the surface(electron depletion). The results are sound and shed new light on the most recent findings in this field. On the basis of the present first-principles results, we propose a Thomas–Fermi model of the impurity screening in silicon nanocrystals. The model gives reliableestimations of the screening function, that well compares to recent ab-initio calculations.Pubblicazioni consigliate
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