Theory of the Electronic and Optical Properties of InGaAs/GaAs Quantum Dots

Abstract

The continuous progress in epitaxial growth and patterning technology has opened far reaching possibilities to fabricate isolated semiconductor hete-rostructures which exhibit quantum confinement of charge carriers in all three spatial dimensions, called quantum dots (QD) [1, 2, 3, 4, 5]. The wave vector spaces of confined electrons and holes in QDs are zero-dimensional (0D), giving rise to unique optical properties. Theoretical predictions of the electronic properties of semiconductor QDs are relevant as link between experimental investigations of the structural and optical properties of such systems. Thereby, complex numerical models are necessary to capture the intricate impact of the real structure on the electronic and optical properties. The inhomogeneous strain inherently connected to the Stranski-Krastanow mode formation of QDs in the InGaAs/GaAs material system [1] strongly influences also their electronic structure. Band mixing effects, enhanced by low confinement symmetry and strain, are of equal significance. These insights promoted the use of various perturbation [6, 7, 8, 9] and multi-band models [10, 11, 12, 13, 14, 15] for the electronic structure in combination with adiabatic treatments of the strain effects [16,17], as well as tight-binding [18] and pseudopotential calculations [19, 20, 21, 22].