The researches of a surface morphology, electrophysical characteristics and gas sensitivity of the metal-silicon structures with a surface layer of the porous silicon modified by platinum and copper were carried out. It was shown, that the mechanism of hydrogen sulphide adsorption in structures with layers of nanoporous silicon filled by copper consists in chemical interaction of hydrogen sulphide molecules with copper atoms and formation of the new phase CuS which leads to change of the metal-silicon Schottky barrier. Restoration of such structures it is possible due to warming up in 50 % Ar and Í2 mixture at temperature up to 300°Ñ. It was established, that application of thin layers of nanoporous silicon filled by copper leads to strengthening adsorption-electrical effects in Al-PS (Cu)-Si structures. The connection between morphology, a chemical compound of nanoporous silicon and sensitivity of Schottky structures to hydrogen sulphide were investigated. The mechanism of adsorption strengthening of the hydrogen-containing gas molecules, in particular, hydrogen sulphide was established. In case of structures with layers of porous silicon modified by platinum the mechanism of gas sensitivity is determined by presence of an intermediate porous layer, catalytically active metal (Pt), type of silicon substrate conductivity and parameters of the adsorbed molecules. It was established, that the increase in thickness of the intermediate porous layer causes the increase in gas sensitivity of the surface-barrier structures. The influence on the structure gas sensitivity of the gas environment (the sated vapors and acetone), manufacturing techniques and an operating mode of the surface-barrier structures was determined.