Porous silicon with embedded metal oxides for gas sensing applications

This paper presents an analysis of the sol deposition process on porous silicon in order to produce highly sensitive gas detectors. Sol solutions were deposited within the dendrite structural pore regions of n-type silicon. The parameters for the structures, built of metal oxides (Fe, Ni, Sn), were analyzed. A morphological study of porous silicon, with embedded metal oxide nanocomposites, was carried out using atomic force microscopy. Cross-sections of porous silicon were examined using a scanning electron microscopy. Impedance spectroscopy was used to study the electrical properties of nanomaterials, based on porous silicon, with embedded metal oxide nanocomposites. Gas-sensitivity measurements of the synthesized samples were made. It turned out that, applying variable frequency interference to the sensory structures in a changing environment, changes the impedance response of gas. New perspectives for increasing sensitivity and selectivity are shown.