We have investigated the electron transport properties and the atomic morphology of AlSb/InAs/ AlSb quantum wells (QW) grown by molecular-beam epitaxy. Different shutter sequences were used in producing an InSb-like interface. The highest mobility was obtained for a QW width of 15 rim and an InSb-lik-e interface grown by two growth interruptions, one before and one after the deposition of one indium monolayer. For this shutter sequence, several samples with an InAs channel width from 6 to 25 rim were grown and characterized using high-resolution transmission electron microscopy, classical, and quantum Hall measurements. For a channel width less than 15 rim, the interface roughness becomes dominant, leading to a sharp decrease in the electron mobility. The electron effective mass determined by the temperature dependence of the Shubnikov-de Haas oscillazion amplitude is 0.0374m(0). Transmission electron microscopy images show an atomically abrupt interface and disordered regions directly above the AlSb/InAs interface which can be as large as 2.4 nm.