Density-functional and many body perturbation theory calculations have been carried out in order to study the optical properties both in the ground and excited state configurations, of silicon nanocrystals in different conditions of surface passivation. Starting from hydrogenated clusters, we have considered different Si/O bonding geometries at the interface. We provide strong evidence that not only the quantum confinement effect but also the chemistry at the interface has to be taken into account in order to understand the physical properties of these systems. In particular, we show that only the presence of a surface Si-O-Si bridge bond induces an excitonic peak in the emission-related spectra, redshifted with respect to the absorption onset, able to provide an explanation for both the observed Stokes shift and the near-visible PL experimentally observed in Si-nc. For the silicon nanocrystals embedded in a SiO2 matrix, the optical properties are discussed in detail. The strong interplay between the nanocrystal and the surrounding host environment and the active role of the interface region between them is pointed out, in very good agreement with the experimental results. For each system considered, optical gain calculations have been carried out giving some insights on the system characteristics necessary to optimize the gain performance of Si-nc. To cite this article: E. Degoli et al., C. R. Physique 10 (2009).

Ab-initio calculations of luminescence and optical gain properties in silicon nanostructures / E. Degoli, R. Guerra, F. Iori, R. Magri, I. Marri, O. Pulci, O. Bisi, S. Ossicini. - In: COMPTES RENDUS PHYSIQUE. - ISSN 1631-0705. - 10:6(2009), pp. 575-586. [10.1016/j.crhy.2008.09.003]

Ab-initio calculations of luminescence and optical gain properties in silicon nanostructures

R. Guerra
Secondo
;
2009

Abstract

Density-functional and many body perturbation theory calculations have been carried out in order to study the optical properties both in the ground and excited state configurations, of silicon nanocrystals in different conditions of surface passivation. Starting from hydrogenated clusters, we have considered different Si/O bonding geometries at the interface. We provide strong evidence that not only the quantum confinement effect but also the chemistry at the interface has to be taken into account in order to understand the physical properties of these systems. In particular, we show that only the presence of a surface Si-O-Si bridge bond induces an excitonic peak in the emission-related spectra, redshifted with respect to the absorption onset, able to provide an explanation for both the observed Stokes shift and the near-visible PL experimentally observed in Si-nc. For the silicon nanocrystals embedded in a SiO2 matrix, the optical properties are discussed in detail. The strong interplay between the nanocrystal and the surrounding host environment and the active role of the interface region between them is pointed out, in very good agreement with the experimental results. For each system considered, optical gain calculations have been carried out giving some insights on the system characteristics necessary to optimize the gain performance of Si-nc. To cite this article: E. Degoli et al., C. R. Physique 10 (2009).
Nanocrystals; Silicon; Optical properties; Gain
Settore FIS/03 - Fisica della Materia
Article (author)
File in questo prodotto:
File Dimensione Formato  
Comptes rendus - Physique 10 575-586 (2009).pdf

accesso riservato

Tipologia: Publisher's version/PDF
Dimensione 834.27 kB
Formato Adobe PDF
834.27 kB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/502240
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 25
  • ???jsp.display-item.citation.isi??? 23
social impact