Enhanced surface cation mobility on Sn delta-doped (Ga,Al)As

During the growth of GaAs and AlAs on vicinal GaAs(100) by molecular-beam epitaxy, reflection high energy electron diffraction was used to measure the transition temperature between two-dimensional nucleation and pure step propagation when submonolayer amounts of Sn were present on the surface. On samples misoriented by 0.5°to either the [011] or the [011̄] direction, the transition temperature decreased by approximately 100°C after the deposition of 0.6 monolayers of Sn, indicating that the Ga mobility increased. The presence of Sn also increased the surface mobility of the Al adatoms on AlAs(100) surfaces as indicated by the annealing behavior of the AlAs surface at 600°C.