Theoretical and experimental aspects of the growth of heterostructures were investigated. In these heterostructures, GaAs was grown on top of the buried metal layer via migration-enhanced epitaxy at low temperatures (200 or 400C) in order to provide a kinetic barrier to the out-diffusion of Al during super-layer growth. The crystallinity and orientation of the Al film which was deposited on (100)GaAs at about 0C was studied by using transmission electron diffraction, dark-field imaging, and X-ray diffraction methods. It was found that the Al was polycrystalline, with a grain size of about 6nm, and that the preferred growth orientation was (111). This could be textured in the plane, but oriented out of the plane. The quality of the GaAs super-layer, which was grown on top of the Al by means of migration-enhanced epitaxy, was very sensitive to the growth temperature. A layer which was grown at 400C had a good structural and optical quality, but was associated with considerable Al out-diffusion at the Al/GaAs hetero-interface. At 200C, where the interface had good structural integrity, the super-layer exhibited twinning and no luminescence was observed.

P.Bhattacharya, J.E.Oh, J.Singh, D.Biswas, R.Clarke, W.Dos Passos, R.Merlin, N.Mestres, K.H.Chang, R.Gibala: Journal of Applied Physics, 1990, 67[8], 3700-5