AlxIn1-xAs1-ySby/GaSb effective mass superlattices grown by molecular beamepitaxy

A detailed study of the growth of AlxIn1-xAs1-ySby/GaSb multilayers on GaSb (1 0 0) substrates by molecular beam epitaxy (MBE) has been performed as pa rt of an investigation for the use of this materials system for kinetic het erojunctions (KHJs). KHJs exploit kinetic energy variations brought about b y an effective mass discontinuity across the junction. Multiple kinetic het erojunctions or effective mass superlattices (EMSs) are predicted to exhibi t unique features, such as equally spaced subbands. not found in convention al superlattices which may lead to a new generation of devices based on kin etic confinement rather than potential confinemnet. AlxIn1-xAs1-rSby/GaSb E MSs were synthesized by MBE focusing on tailoring the composition such that there is a zero conduction band offset at the Gamma point, a zero modulati on of the electron affinity and lattice matching across the heterojunction facilitating studies of purely kinetic effects. This is achieved when x = y congruent to 0.5. which lies in the center of the predicted miscibility ga p. therefore: a detailed study of the growth of the quaternary has been per formed. High-quality EMSs were grown in the range (0.3 less than or equal t o x less than or equal to 0.6. 0.5 less than or equal to y less than or equ al to 1.0) as assessed by X-ray diffraction. Magneto-transport measurements were performed to determine layer mobility and conductivity. Shubnikov-de Haas (SdH) analyses were performed to verify two-dimensional carrier confin ement. (C) 1999 Elsevier Science B.V. All rights reserved.