کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5404031 | 1392771 | 2006 | 5 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Doping in silicon nanocrystals: An ab initio study of the structural, electronic and optical properties
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
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چکیده انگلیسی
There are experimental evidences that doping control at the nanoscale can significantly modify the optical properties with respect to the pure systems. This is the case of silicon nanocrystals (Si-nc), for which it has been shown that the photoluminescence (PL) peak can be tuned also below the bulk Si band gap by properly controlling the impurities, for example by boron (B) and phosphorus (P) codoping. In this work, we report on an ab initio study of impurity states in Si-nc. We consider B and P substitutional impurities for Si-nc with a diameter up to 2.2Â nm. Formation energies (FEs), electronic, optical and structural properties have been determined as a function of the cluster dimension. For both B-doped and P-doped Si-nc the FE increases on decreasing the dimension, showing that the substitutional doping gets progressively more difficult for the smaller nanocrystals. Moreover, subsurface impurity positions result to be the most stable ones. The codoping reduces the FE strongly favoring this process with respect to the simple n-doping or p-doping. Such an effect can be attributed to charge compensation between the donor and the acceptor atoms. Moreover, smaller structural deformations, with respect to n-doped and p-doped cases, localized only around the impurity sites are observed. The band gap and the optical threshold are largely reduced with respect to the undoped Si-nc showing the possibility of an impurity-based engineering of the Si-nc PL properties.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Luminescence - Volume 121, Issue 2, December 2006, Pages 335-339
Journal: Journal of Luminescence - Volume 121, Issue 2, December 2006, Pages 335-339
نویسندگان
Federico Iori, Elena Degoli, Eleonora Luppi, Rita Magri, Ivan Marri, G. Cantele, D. Ninno, F. Trani, Stefano Ossicini,