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Bulgarian Journal of Physics
Print: 1310-0157 Online: 1314-2666
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RECOGNIZED BY THE EUROPEAN PHYSICAL SOCIETY 
Bulg. J. Phys. vol.25 no.5-6 (1998), pp. 248-255
Investigation of Ethanol Vapours Adsorption on the Oxide Surface of Si-SiO2 Structures by Vibrating Kelvin Electrode Method
S.S. Georgiev, J.B. Koprinarova
Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd, 1784 Sofia, Bulgaria
go backInstitute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd, 1784 Sofia, Bulgaria
Abstract. The change in contact potential difference due to ethanol vapours adsorption by Si-SiO2 structures with different oxide kinds is measured by Kelvin's method. Two types of electrical active adsorption were established — reversible and nonreversible. Relatively high sensitivity of the reversible adsorption demonstrated structures with ultrathin oxide and structures with plasma SiO2 deposited from SiCl4 and O2. The reversible ethanol vapours adsorption onto the oxide surface of a Si-SiO2 structure with plasma deposited SiO2 layer creates positively charged states near the Fermi level (above 0.05 eV), while the nonreversible — other states at 0.9 eV above the Fermi level.