Tight-Binding Method and Multiband Effective Mass Theory Applied to CdS Nanocrystals: Single-Particle Effects and Optical Spectra Fine Structure

Published

October 12, 2021

Author(s)

J G. Diaz-Garcia, J Planelles, Garnett W. Bryant, Javier Aizpurua

Abstract

Optical spectra of CdS nanocrystals are interpreted by using both the atomistic tight-binding method and multiband effective-mass theory. Both methods correctly describe the energy splitting between the two lowestoptically active transitions and their relative strengths, providing the same labeling of the two main absorption peaks of the spectrum. Our calculations unambiguously show that these peaks correspond to the 1S(3/2) to 1s and 1P(3/2) to 1p transitions. Both zincblende and wurtzite-type structures for CdS nanocrystals are considered. Similar optical spectra are predicted for the two lattice structures. We also study how the spectrum, and in particular the 1S(3/2) - 1S(1/2) splitting, is changed by modifying parameters, within the experimentaluncertainties, including size and shape fluctuations, surface passivation and spin-orbit coupling. Our results are robust to small variations in all of these parameters.

Citation

Journal of Physical Chemistry Part B Condensed Matter, Materials, Surfaces, Interfaces & Biophysical

Pub Type

Journals

Keywords

electronic structure, nanocrystals, optical spectra, quantum dots, tight-binding

Citation

Diaz-Garcia, J. , Planelles, J. , Bryant, G. and Aizpurua, J. (2021), Tight-Binding Method and Multiband Effective Mass Theory Applied to CdS Nanocrystals: Single-Particle Effects and Optical Spectra Fine Structure, Journal of Physical Chemistry Part B Condensed Matter, Materials, Surfaces, Interfaces & Biophysical (Accessed May 5, 2024)