It was found that the crystal quality, electron mobility and electron density of InAs single-crystal thin films grown directly on GaAs (10 0) substrates have a strong dependence on the film thickness. Moreover, tin doping increased the electron mobility compared to that of undoped InAs thin films. In addition, the tin doping reduced the temperature dependence of electron mobility and electron density of the InAs thin films. It is concluded from these results that tin doping during MBE growth of InAs can produce InAs single-crystal thin films suitable for magnetic sensors with a wide range of operation temperatures. © 2005 Elsevier B.V. All rights reserved.