Influence of well-width fluctuations on the binding energy of excitons, charged excitons, and biexcitons in GaAs-based quantum wells

We present a first-principle path integral Monte Carlo (PIMC) study of the binding energy of excitons, trions (positively and negatively charged excitons) and biexcitons bound to single-island interface defects in quasi-two-dimensional GaAs/AlxGa1-x As quantum wells. We discuss in detail the dependence of the binding energy on the size of the well-width fluctuations and on the quantum-well width. The numerical results for the well-width dependence of the exciton, trions and biexciton binding energy are in good quantitative agreement with the available experimental data.