Origins of visible-light emissions in hydrogen-coated silicon nanocrystals: Role of passivating coating

Nacir Tit*, Z. H. Yamani, J. Graham, A. Ayesh

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

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.

Original languageEnglish
Pages (from-to)2226-2237
Number of pages12
JournalJournal of Luminescence
Volume130
Issue number11
DOIs
StatePublished - Nov 2010

Bibliographical note

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.

Keywords

  • Electronic structure of quantum dots
  • Optical properties of nanoparticles
  • Photoluminescence

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • General Chemistry
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics

Fingerprint

Dive into the research topics of 'Origins of visible-light emissions in hydrogen-coated silicon nanocrystals: Role of passivating coating'. Together they form a unique fingerprint.

Cite this