Pseudopotential Theory of Electronic Excitations in Semiconductor Nanostructures

Abstract

The calculation of the optical and electronic properties of semiconductor nanostructures is still based for the most part on highly approximated, continuum-like models such as the effective-mass approximation, which do not take into account the atomistic structure of the nanostructures. We present here an atomistic pseudopotential approach to the calculation of excited states in semiconductor nanostructures. The single-particle Schroedinger equation is solved using O(N) methods. The electronic excited states (such as excitons, charged excitons, multi-excitons, etc.) are then calculated by solving the many-particle Schroedinger equation in a basis set of Slater determinants obtained by promoting one or more electrons from the valence band to the conductions band (configuration interaction expansion). Applications of this method to predict the excitonic fine structure and the optical emission spectra of neutral and charged excitons, bi-excitons, and tri-excitons in CdSe colloidal nanocrystals are presented.