Electrode effects in electrical measurements in SiO thin films

We report results obtained from thermally stimulated current and capacitance measurements of metal-SiO-metal structures having different metals for the electrodes. Dependence of relaxed charge on the polarized electrode suggests the existence of space charge near the metal-insulator interface. The measurements of capacitance under superimposed DC voltages support this interpretation and show that space charge is not negligible at high fields. The density of lacalised states evaluated from the data is of the order of 10¹⁷ cm^?3