Session WC09 - Fundamentals of Heteroepitaxy II: III-V Semiconductors.
FOCUS session, Thursday afternoon, March 25
Room 363W, GWCC
Lateral composition modulations, lateral superlattices and aligned quantum dot arrays can form during the heteroepitaxial growth of misfitting multilayer films, as recently observed in InAs/AlAs, InGaP/InGaAsP, InAs/GaAs, InGaP/GaAs, and SiGe multilayers. We examine the growth of stress-driven morphological instabilities during the deposition of multilayer films. The instabilities are analyzed using continuum elasticity and perturbation theory, where each layer grows on the non-flat surface of the layer below it. Each layer has a different misfit, surface energy, surface diffusivity, growth rate and thickness and all morphological evolution occurs via surface diffusion. The morphological instabilities of adjacent layers can be either in-phase or out-of-phase and can produce lateral composition modulations of the same wavelength as the surface morphology. Conditions under which such modulations occurs and where they lead to break-up of the layers into lateral superlattices are delineated as a function of both material and geometric parameters. These predictions are compared with experimental observations of InAs/AlAs on InP.