TY - JOUR
T1 - Origins of visible-light emissions in hydrogen-coated silicon nanocrystals
T2 - Role of passivating coating
AU - Tit, Nacir
AU - Yamani, Z. H.
AU - Graham, J.
AU - Ayesh, A.
N1 - Funding Information:
This work started during the visit of one of us (N.T.) to the CENT-KFUPM (Saudi Arabia) in summer 2009 under a financial support provided by the CENT. Special thanks are due to Fabio Trani for his technical support. The authors are indebted to extend their thanks to Anane Alkarmi, Jim Chelikowsky, Serdar Ögüt, Ali Reshak and Bashar Issa for many fruitful discussions. Partial financial support from the side of UAE University was provided via the Research Affairs under Grant number 08-02-2-11/09 . This work is also supported by Emirates Foundation.
PY - 2010/11
Y1 - 2010/11
N2 - We present a theoretical investigation of the electronic and optical properties of hydrogen-coated silicon nanocrystals (Si:H NCs). On one hand, the density-functional theory (DFT) is used to both calculate the total energy and relax the NCs. On a second hand, the tight-binding method, which includes the minimal sp3+-basis set within the second-nearest-neighbor interaction scheme, is applied to calculate the electronic structures, oscillator strength (OS) and recombination rate (RR) versus the NC size, coating and atomic relaxation. Three main findings are reported: (i) The quantum confinement in these NCs do follow similar rule to the case of a single-particle in a box, where the confinement energy decays in power-law with the increasing NC's size. (ii) The coating is shown to play the essential role in creation of large band-gap energy lying within the visible-light energy spectrum. (iii) The surface atomic relaxation is found to reduce the band-gap energy by about 150 meV and enhance both OS and RR. Our claims are corroborated by the available experimental data.
AB - We present a theoretical investigation of the electronic and optical properties of hydrogen-coated silicon nanocrystals (Si:H NCs). On one hand, the density-functional theory (DFT) is used to both calculate the total energy and relax the NCs. On a second hand, the tight-binding method, which includes the minimal sp3+-basis set within the second-nearest-neighbor interaction scheme, is applied to calculate the electronic structures, oscillator strength (OS) and recombination rate (RR) versus the NC size, coating and atomic relaxation. Three main findings are reported: (i) The quantum confinement in these NCs do follow similar rule to the case of a single-particle in a box, where the confinement energy decays in power-law with the increasing NC's size. (ii) The coating is shown to play the essential role in creation of large band-gap energy lying within the visible-light energy spectrum. (iii) The surface atomic relaxation is found to reduce the band-gap energy by about 150 meV and enhance both OS and RR. Our claims are corroborated by the available experimental data.
KW - Electronic structure of quantum dots
KW - Optical properties of nanoparticles
KW - Photoluminescence
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U2 - 10.1016/j.jlumin.2010.06.025
DO - 10.1016/j.jlumin.2010.06.025
M3 - Article
AN - SCOPUS:78049426453
SN - 0022-2313
VL - 130
SP - 2226
EP - 2237
JO - Journal of Luminescence
JF - Journal of Luminescence
IS - 11
ER -