Growth of InGaSb/AlSb high hole mobility quantum well field effect transistors (QW FETs) on Si substrates with a step-graded GaAsSb metamorphic buffer layer by molecular beam epitaxy is explored. With an optimized growth temperature for the InGaSb/AlSb QW, hole mobility of 770 cm(2)/V s and 3060 cm(2)/V s have been achieved at room temperature and 77 K, respectively, It is also found that the twins in the samples do not cause significant anisotropic behavior of the InGaSb QW FETs in term of gate direction. (C) 2015 Elsevier B.V. All rights reserved.