Molecular beam epitaxy growth of InAs/AlSb superlattices on GaAs substrates

Abstract

We report on the molecular beam epitaxial growth of 13ML InAs/5ML AlSb type-II superlattice on highly lattice mismatched GaAs (0 0 1) substrate. The high lattice mismatch of 7.35% between the superlattice and GaAs substrate is reduced by the growth of GaSb buffer layer based on interfacial misfit array technique. This latter consists on the instantaneous relieving of the strain at the GaAs/GaSb interface by the formation of a periodic array of 90° misfit dislocations. On the other hand, the strain in the InAs/AlSb superlattice has been compensated by a special shutters sequence that leads to the formation of both AlAs-like and InSb-like interfaces. In addition, the grown superlattice has been deposited at relatively low growth temperature compared to that reported in the literature. Under optimized growth conditions, the InAs/AlSb superlattice exhibit good structural, and optical properties.