MOLECULAR-BEAM EPITAXIAL-GROWTH OF INASSB STRAINED LAYER SUPERLATTICES - CAN NATURE DO IT BETTER

Molecular beam epitaxial growth of a normally homogeneous InAs0.5Sb0.5 alloy below 430-degrees-C results in its coherent phase separation into platelets of two different alloy compositions with tetragonally distorted crystal lattices. This produces a "natural" strained layer superlattice (n-SLS) with clearly defined interfaces modulated in the [001] growth direction. A description of the n-SLS growth mode in InAsSb is outlined, and the optical response of a n-SLS structure, which extends to 12.5-mu-m-considerably further than that of a homogeneous InAs0.5Sb0.5 layer (8.9-mu-m)-is reported.