Modelling of the composition segregation effect during epitaxial growth of InGaAs quantum well heterostructures

Using a Monte Carlo (MC) technique, we performed numerical modelling of the kinetic segregation effect during epitaxial growth of a heterostructure containing an IncGa1−cAs quantum well (QW) surrounded by two GaAs barriers. The growth occurs in the direction coinciding with or slightly tilted from [0 0 1]. The model of growth kinetics takes into account the effect of pseudomorphic deformation of the underlying atomic layers onto the activation energy of adatom diffusion in the growing monolayer. It influences the surface segregation of In atoms and affects the QW shape. Within the effective mass approximation, the dependence of the lowest electron–hole transition energy on the degree of In/Ga segregation (in turn, depending upon the growth conditions and substrate tilting angle) was calculated. The calculations were performed using the composition profiles obtained from the MC modelling and taking into account the corresponding distribution of the elastic strain. The results show that the segregation effect leads to a considerable blue shift and broadening of the QW photoluminescence (PL) peak which increase for higher growth temperatures and lower values of the total cation flux from the gas phase onto the growing surface. Growth on vicinal substrates leads to a reduction of the PL peak broadening