The growth of InAlAsSb by metal-organic vapor phase epitaxy has been demonstrated, with a controllable antimony fraction exceeding 6%. Calculations have shown that InAlAsSb with Sb contents greater than 5-7% in the quaternary are within the miscibility gap, however this work demonstrates specific growth conditions that allow compositions well within the miscibility gap. From a study of the growth of AlAsSb and an evaluation of two aluminum precursors (TMAl versus TTBAI), growth temperature, and V/III ratio, a foundation is developed to optimize the growth of InAlAsSb. By tailoring V/III ratio, growth conditions were found to achieve high crystalline content of both indium and antimony. InAlAsSb was grown on InP with antimony fractions from 32% to 48%, for which indium fraction varied from 10% to 19%, which provides an expected direct bandgap ranging from 1.75 to 1.98 eV. (C) 2017 Elsevier B.V. All rights reserved.