Er doped Gd oxide thin films were prepared by alternating deposition method on Si (P) substrates to form MOS structures. These films were annealed in oxygen atmosphere and in vacuum and characterised by X-ray fluorescence and X-ray diffraction. The capacitance-gate voltage (C-V-g) dependence was used to characterise the constructed MOS devices and to measure the relative permittivity of the oxide. The dc-current transfer in the samples was studied as a function of gate voltage and temperature in the range of (293-343 K). The measurements showed that for voltages V > 0.8 V, the current transfer followed the trap-charge-limited space-charge-limited conductivity (TCLC-SCLC) mechanism characterised by exponential distribution of traps within the bandgap. The energy distribution of traps and their total concentration were determined. (c) 2004 Elsevier B.V. All rights reserved.