Kostiukevych O. The influence of transient processes on the formation of the adsorption response of nanomaterials-based gas-sensitive structures

The dissertation is devoted to the study of the physical and chemical features of the formation of current, capacitive and resistive adsorption responses in gas-sensitive metal-semiconductor contacts with thin intermediate films of ITO, heterostructures based on layers of titanium, zinc and indium-tin oxides, photovoltaic cells, free layers of porous SiC, as well as the study of the influence of trap-induced transient processes on the adsorption sensitivity of the semiconductor structures and the possibility of using the selective parameters of these transient processes for the discrimination of chemical compounds or formation of the olfactory image of gas environment. Based on the analysis of adsorption-stimulated changes in current-voltage characteristics, it was shown for the first time that the reason for the increase of the reverse current through the p-Si/Ni contact with nano-sized ITO film under the influence of the adsorption of ethyl and isopropyl alcohol molecules at a constant applied bias voltage is the physical effect of decrease of the potential barrier height in the oxide film, caused by a change in the potential of the image forces acting on minority charge carriers in the interface. The change in the potential of the image forces, in turn, is caused by variations in the dielectric constant of the film as a result of adsorption and subsequent migration of analyte molecules into its volume.