Abstract—GaSb quantum dots (QDs) in a GaAs matrix have attracted much attention for the potential ability to extend the accessible wavelength of QD emitters towards a wavelength of > 1.3 μm owing to their unique electronic and optical properties caused by their staggered (type-II) band alignment. North et al. calculated the electronic structure of self-assembled GaSb/GaAs dots by using the simple one-band model (effective mass model). Therefore it is interesting to carry out the detailed calculations using a more accurate method, in particular in the view of the new experiments. The aim of this work is to study the electronic properties of GaSb/GaAs self-assembled quantum dots (SAD) by using the sp³s^* empirical tight-binding method. The influence of strain on the electronic structure is determined by minimizing the elastic energy within the Valence Force Field Approach and the piezoelectric potential is calculated by solving the corresponding 3D Poisson equation. Single-particle bound-state energies are computed as a function of the dot sizes. Finally we have found that the theoretical PL spectra are in a good agreement with the experiment and k.p method.

Index Terms—Tight-binding method, quantum dot, strain distribution and piezoelectricity.

W. Sukkabot is with Department of Physics Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, 34190 Thailand (e-mail: w.sukkabot@gmail.com).

Cite:W. Sukkabot, "Electronic Structure of Strained GaSb/GaAs Quantum Dot: Tight-Binding Approach," International Journal of Applied Physics and Mathematics vol. 3, no. 3, pp. 178-181, 2013.