Study of interfaces in GaInSb InAs quantum wells by high-resolution X-ray diffraction and reciprocal space mapping

The electrical and optical properties of advanced epitaxial structures, suc h as quantum wells and superlattices are strongly influenced by the quality of their interfaces. The GaInSb/InAs system is particularly important beca use of its promise for use in infrared detection in the 8-14 mu m ranges, I n this material system the two compounds do not share a common anion, and d ifferent bond types exist at the interface depending upon the growth parame ters. We have looked at single quantum-well structures grows with solid sou rce molecular beam epitaxy such that a distinct interface type would be fou nd in each sample. X-ray rocking curves and full dynamical simulations were performed for each quantum well structure. Quantum wells with three types of interfaces were grown and analyzed; random interfaces, Sb-like interface s. and As-like interfaces formed with a one monolayer group III deposition follow cd by a five second group V soak. With the exception of the interfac es, all three sows have nominally the same structure; 5000 Angstrom of GaSb buffer layer grown upon a GaSb substrate, a 150 Angstrom quantum well with 35 Angstrom Ga0.75In0.25Sb barriers and a final GaSb cap layer of 50 Angst rom thickness. Well-resolved Pendellosung fringes were found in all samples indicating high quality in the epitaxial layers and interfaces. The SQW wi th the As-like interfaces had the highest degree of quality as evidenced by persistence of the fringes. (C) 1999 Elsevier Science B.V. All rights rese rved.