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/Al$_{x}$Ga$_{1-x}$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. 
A.V. Filinov, C. Riva, F.M. Peeters, Yu.E. Lozovik, and M. Bonitz