Growth mode and dislocation distribution in the ZnSe/GaAs (100) system

We have investigated the effect of the initial growth mode on the dislocation structure in ZnSe epilayers grown on GaAs(100) by molecular beam epitaxy. For the case where the initial growth occurred by the formation and coalescence of three-dimensional islands, the threading dislocation density was found to be an order of magnitude higher and misfit dislocation lengths much shorter than that for the case where the initial growth proceeded by a two-dimensional layer-by-layer mode. These differences are discussed in terms of dislocation formation at island coalescence boundaries for a three-dimensional growth mode.