It was shown that the presence of low-temperature-grown GaAs, in GaAs/AlAs on Si-doped GaAs heterostructures, increased Al/Ga interdiffusion at the heterostructure interfaces. The interdiffusivity enhancement was attributed to the presence of Ga vacancies, VGa, in the As-rich low-temperature GaAs, which diffused from a supersaturation of VGa which was frozen in during growth. Chemical mapping, which distinguished between the AlAs and GaAs lattices at the atomic scale, was used to measure the Al concentration gradient in adjacent Si-doped GaAs layers.

C.Kisielowski, A.R.Calawa, Z.Liliental-Weber: Journal of Applied Physics, 1996, 80[1], 156-60