Many-Body Levels of Optically Excited and Multiple Charged InAs Nanocrystals Modeled by Semiempirical Tight Binding

Published

December 1, 2002

Author(s)

S Lee, J Kim, P. Jonsson, J W. Wilkins, Garnett W. Bryant, G Klimeck

Abstract

Many-body levels of optically excited and multiple charged InAs nanocrystals are studied with the empirical tight-binding model. Single-particle levels of unstrained spherical InAs nanocrystals are described by the sp^3u5 s* nearest-neighbor tight-binding model including spin-orbit coupling. For the optically excited InAs nanocrystals, first-order corrections of electron-hole Coulomb and exchange interaction to exciton levels and the oscillator strengths of the exciton levels determine several low-lying, bright-exciton levels. The origin of the bright exciton levels is revealed by the analysis of dominant angular momenta of exciton envelope functions. Good agreement with photoluminescence excitation experiments is achieved in the size dependence of the three lowest bright-exciton energies for nanocrystals with radius larger than 20 . For the multiply charged InAs nanocrystals, polarization of the nanocrystal environment is approximated by modeling the environment with a uniform dielectric medium. This polarization model incorporated into the tight-binding model provides a reasonable description of electron and hole addition energies in scanning tunneling spectroscopy experiments.

Citation

Physical Review B (Condensed Matter and Materials Physics)

Volume

66

Issue

NO. 23

Pub Type

Journals

Keywords

electronic structure, nanocrystals, photoluminescence, quantum dots, tight-binding theory, tunneling

Citation

Lee, S. , Kim, J. , Jonsson, P. , Wilkins, J. , Bryant, G. and Klimeck, G. (2002), Many-Body Levels of Optically Excited and Multiple Charged InAs Nanocrystals Modeled by Semiempirical Tight Binding, Physical Review B (Condensed Matter and Materials Physics) (Accessed December 12, 2024)