Samples of thin (Gd-In) oxide film were prepared on quartz and Si(P) substrates for optical and electrical investigations. These samples were annealed at different conditions and characterised by UV-Vis absorption spectroscopy, X-ray fluorescence (XRF) and X-ray diffraction (XRD). The AC-conductance and capacitance were studied as a function of frequency, temperature, and gate voltage. The 'corrected barrier hopping' CBH model controls the frequency dependence of the conductivity and capacitance. Good oxide-Si interface properties due to low midgap interface state density was observed for (Gd-In) oxide sample annealed in vacuum. (C) 2004 Elsevier B.V. All rights reserved.