The characterization of III-V semiconductor films by contactless and non-invasive conductance and transient photoconductance measurements in the microwave frequency range were investigated. It was shown that the conductivity (of a GaSb film) and the majority carrier mobility (of GaAs and InP films) can be determined. Besides, information on charge carrier transport, in particular at the surface is obtained. (C) 2003 Elsevier B.V. All rights reserved.