Effect of symmetry breaking on the optical absorption of semiconductor nanoparticles

A. Gali, Efthimios Kaxiras, Gergely T. Zimanyi, Sheng Meng

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The shape of semiconductor nanoparticles (NPs) can have an important influence on their optical absorption spectra with enhanced absorption resulting from breaking their symmetries. To illustrate this effect, we present broad energy optical excitation spectra of ∼2 nm Si and PbSe nanoparticles, obtained from extensive time-dependent density functional theory calculations. We considered both highly symmetric spherical shapes and low-symmetry rodlike and disklike shapes. The low-symmetry shapes exhibit an increase in absorption at low and relatively high energies compared to the absorption of spherical NPs of similar volume, independent of their chemical compositions and surface structures. Our results elucidate the mechanism of enhanced multiexciton generation in semiconductor NPs, which is important in the quest to improve their photovoltaic applications.

Original languageEnglish
Article number035325
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume84
Issue number3
DOIs
Publication statusPublished - Jul 11 2011

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Crystal symmetry
Light absorption
broken symmetry
optical absorption
Semiconductor materials
Nanoparticles
nanoparticles
Photoexcitation
symmetry
Surface structure
Density functional theory
optical spectrum
Absorption spectra
chemical composition
density functional theory
absorption spectra
energy
Chemical analysis
excitation

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Effect of symmetry breaking on the optical absorption of semiconductor nanoparticles. / Gali, A.; Kaxiras, Efthimios; Zimanyi, Gergely T.; Meng, Sheng.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 84, No. 3, 035325, 11.07.2011.

Research output: Contribution to journalArticle

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