Morphology of InAs self-organized islands on AlAs surfaces

Abstract
We report an in situ molecular-beam epitaxy-scanning tunneling microscopy study of three-dimensional (3D) self-organized InAs islands on AlAs surfaces. The evolution of the density and morphology of these islands is investigated as a function of the InAs coverage and substrate temperature. It is shown that the 2D island density is already high just prior to 3D island formation and remains constant for 3D structures as the InAs coverage is increased. This observation contrasts with the InAs/GaAs system and makes possible the growth of very high densities of small quantum dots.