We investigated the thickness dependence of structural and electrical properties of polycrystalline InAs layers grown on glass substrates at a substrate temperature of 230 degrees C by molecular-beam deposition. Degradation in electron mobility with decreasing thickness is shown and is attributed not only to the decrease in crystallite size but also to the existence of a defective layer adjacent to the substrate. In order to investigate the effectiveness of GaSbAs as buffer layers on these problems, polycrystalline InAs layers of 0.1 mu m thickness were gown with GaSbAs buffer layers of various thicknesses and alloy compositions inserted between the InAs layers and the substrates. It is shown that, in spite of the low substrate temperature of 300 degrees C and the thin thickness of 0.1 mu m, the polycrystalline InAs film can exhibit an electron mobility as high as 600 cm(2)/(V s) by inserting a 0.5-mu m thick GaSbAs buffer layer of an Sb composition around 0.6. (c) 2012 Elsevier B.V. All rights reserved.