InAs0.1Sb0.9 active layers sandwiched between Al0.1In0.9Sb insulating layers were grown on GaAs(I 00) substrates by molecular beam epitaxy (MBE) where the InAs0.1Sb0.9 active layers had no lattice mismatch with the Al0.1In0.9Sb layers. Basic transport properties and electronic properties of the InAs0.1Sb0.9 were studied as functions of InAs0.1Sb0.9 thickness. Very large electron mobility of InAs0.1Sb0.9 active layers and very small thickness dependence at <500nm were observed. The large lattice mismatch effect observed for InSb active layers grown directly on GaAs substrates and for an InSb active layer sandwiched between Al0.1In0.9Sb was almost completely eliminated. (C) 2008 Published by Elsevier B.V.