Thin heteroepitaxial layers of InAs have been grown on (100) GaAs substrates and buffer layers by molecular beam deposition in a UHV chamber. Smooth epitaxial layers as indicated byinsituMEED patterns have been obtained at substrate temperatures in the range 330–530 °C and SEM micrographs and electron channeling patterns takenexsituhave confirmed these properties. MEED observations also indicated that epitaxial growth can be obtained at considerably lower deposition temperatures. InAs films, 0.5–2.0 &mgr;m thick, grown between 330 and 530 °C had bulklike electrical properties with residualn‐type carrier concentrations in the range 5×1016to 1×1018cm−3, the lowest values occurring for depositions at 530 °C.