Metamorphic growth of III-V semiconductor bicrystals

The authors report on the structural properties of III-V semiconductor films that are not lattice matched to the GaAs substrates on which they are grown. Using molecular beam epitaxy, a uniform two-dimensional edge dislocation network is formed that abruptly relaxes the misfit strain at the film/substrate interface. The nucleation and initial growth of a GaSb film on GaAs are analyzed using reflection high-energy electron diffraction to show growth that becomes two dimensional in approximately five monolayers. Comparisons of the experimental reciprocal space map peak shapes and theoretical shapes show that some of these films are approaching the theoretical limit where all of the strain is completely relaxed at the interface. (C) 2011 American Vacuum Society. [DOI: 10.1116/1.3565436]