Epitaxial films of AlAs0.16Sb0.84and Al0.8Ga0.2As0.14Sb0.86were grown lattice matched on (100) InAs substrates by molecular beam epitaxy. The material was characterized by x‐ray diffraction, 4 K photoluminescence, and capacitance‐voltage measurement techniques. At 300 K, background acceptor concentrations of 1.8×1015and 1.4×1016cm−3were determined for the unintentionally doped AlAsSb and AlGaAsSb epitaxial layers, respectively. Compensating the AlAsSb and AlGaAsSb epitaxial layers with sulfur doping resulted in high‐resistivity material with an effective donor concentration of about 1014and 1015cm−3, respectively.