Anisotropic structural and electronic properties of InSb/AlInSb quantum wells grown on GaAs [001] substrates

InSb quantum wells (QWs) with remotely doped Al/sub x/In/sub 1-x/Sb barriers are candidates for several novel device structures that rely on a long electron mean free path. Mesoscopic magnetoresistors that take advantage of the high electron mobility in InSb QWs at room temperature are currently being developed for read-head applications. The promise of InSb QWs for spin-transistor applications has been shown recently by experiments that demonstrate a large zero-field spin splitting and ballistic transport at temperatures as high as 185 K. Since a semi-insulating substrate is required for electronic applications, the InSb/Al/sub x/In/sub 1-x/Sb structures are grown on GaAs [001] substrates. The /spl sim/14% lattice mismatch between the epilayers and the substrate results in a high defect density that partially limits the electron mean free path. We will present a detailed characterization of these defects and elucidate their role in limiting electron mobility.