Use of the method of local cathodoluminescence in Si–TiO 2 and Si–SiO 2 –TiO 2 structures helps to elucidate the nature of centers influencing the operation of memristors. These measurements showed that electroforming leads to the appearance of luminescence in a 250–400 nm wavelength range in the external part of TiO 2 layer characterized by high concentration of defects. This observation leads to a conclusion that a sharp interface is formed between dielectric layers of the structure, provides estimation of the absorption coefficient of TiO 2 layer, and allows its bandgap width (~3.3 eV) to be evaluated for the oxide layers formed by the given technology.