We studied the effects of an AlGaAsSb electron supply layer for InGaAs/InAlAs metamorphic high electron mobility transistors (mHEMTs) on GaAs substrate. By implementing an AlGaAsSb electron supply layer, we drastically improved the electron mobility of InGaAs/InAlAs heterostructures for mHEMTs. An AlGaAsSb electron supply layer for InGaAs/InAlAs heterostructures on GaAs substrates promises high-performance mHEMTs with low production cost. (C) 2011 Elsevier B.V. All rights reserved.