https://doi.org/10.1140/epjb/e2010-10761-0
Multiband tight-binding theory of disordered AxB1-xC semiconductor quantum dots
Application to the optical properties of alloyed CdxZn1-xSe nanocrystals
Institute for Theoretical Physics,
University of Bremen, 28359 Bremen, Germany
Corresponding author: a dmourad@itp.uni-bremen.de
Received:
6
October
2010
Revised:
28
October
2010
Published online:
10
December
2010
Zero-dimensional nanocrystals, as obtained by chemical synthesis, offer a broad range of applications, as their spectrum and thus their excitation gap can be tailored by variation of their size. Additionally, nanocrystals of the type AxB1-xC can be realized by alloying of two pure compound semiconductor materials AC and BC, which allows for a continuous tuning of their absorption and emission spectrum with the concentration x. We use the single-particle energies and wave functions calculated from a multiband sp3 empirical tight-binding model in combination with the configuration interaction scheme to calculate the optical properties of CdxZn1-xSe nanocrystals with a spherical shape. In contrast to common mean-field approaches like the virtual crystal approximation (VCA), we treat the disorder on a microscopic level by taking into account a finite number of realizations for each size and concentration. We then compare the results for the optical properties with recent experimental data and calculate the optical bowing coefficient for further sizes.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2010