Sensory Structures Based on Porous Silicon for Detection of Toxic Gases

Sensitive elements of toxic gas sensors based on the porous silicon structures have been created. Our scanning electron microscopy based studies suggest the formation of pores with a diameter of up to several micrometers that promotes penetration into the porous layer of macromolecules of the toxic gases. Electrical properties of the obtained structures in the modes of direct and alternating currents are investigated using current-voltage characteristics and impedance spectroscopy. Significant dependence of electrical parameters of the sensory elements on the presence in the atmosphere of molecules of morpholide of pelargonic acid is registered. The adsorption sensitivity of the obtained structures is calculated to estimate their sensory properties. It is found that maximum sensitivity of the sensory elements to the molecules of morpholide of pelargonic acid is realized in the range of their concentrations of about 0.4–0.5 %.