Lateral alignment of InGaAs quantum dots as function of spacer thickness

The effects of spacer thickness on lateral alignment and density of InGaAs quantum dots on GaAs(311)B substrates is investigated. As the thickness of the spacer layers is increased, the two-dimensional lateral ordering previously demonstrated on GaAs(311)B is replaced by the one-dimensional dot chains normally observed on GaAs(100). Additionally, the dot density is found to increase proportionally with spacer thickness. The transition of lateral alignment regimes results from two processes competing to dominate the growth mechanism: the elastic anisotropy of the matrix and the characteristics of surface diffusion.