Modelling x-ray scattering from quantum dots using Keating energy-minimised structures

In a traditional analysis of surface x-ray diffraction data, the surface unit cell can be defined by a small set of parameters, and fitting of experimental data is accomplished using well-established procedures. A quantum dot (QD), however, may contain as many as 20,000 atoms, so a different approach to data analysis is required. A method for modelling a quantum dot and relaxing the structure by minimising the Keating energy is presented, and the simulation of x-ray scattering from such models is described. A method is then developed for simulating the alloying of InAs and GaAs inside the QDs using intermediate Keating parameters. This removes the need to relax and average multiple models with randomly distributed atoms, which would increase the computation time significantly.