The features in the formation of oxide porous structures based on SiO2–SnOх

Substrates of the present gas-sensible sensors are fabricated from the porous silicon characterized by a high specific surface. In order to increase stability of the operation and enhance selectivity of these sensors their surface can be covered with metal-containing films. In this work the film of tin oxide was deposited on the surface of porous silicon; this films is characterized by certain advantages such as a wide band gap, low price, high sensibility and in-toxicity of the material. Porous silicon was obtained by electrochemical anodizing of single-crystalline silicon (grade KEF (100)). Porous silicon samples werethen coated with the films of tin oxide applying thermal evaporation in vacuum. When metal-oxide film was deposited on porous silicon its surface became more textured and in addition formation of the great amount of nano-scale granules could be observed. Optical properties of the samples were studied by UV-spectroscopy. The presence of the oxidized tin was found on the surface of porous silicon in the form of SnO. It was shown that thermal deposition of tin on the surface of porous silicon resulted in the change of position and shape of the photoluminescence band. Results presented in the work demonstrated that thermal evaporation in vacuum can be successfully applied for obtaining of the tin oxide films on porous silicon. The elaborated nanocomposites can be used for the fabrication of sensors for gas detection.