X-Ray Diffraction From Buried GaAs/GaSb Interfaces

The initial stage of epitactic growth of GaSb film on GaAs has been studied by X-ray diffraction. On each island the 8% misfit is accommodated by a periodic network composed of two perpendicular sets of Lomer dislocations. This network is already formed at 10A nominal thickness. The relaxation of the e ilayer towards its bulk lattice parameter is almost complete so that a 1√2(15x15) supercell is observed. The behaviour of the dislocation satellites is accurately explained by the presence of a periodic displacement field at and close to the interface. A quantitative fit with a simple elastic model is, however, insufficient to fit the data, implying that interdiffusion occurs close to the interface.