Sensitivity of the a-Si:H/c-Si structure to alcohol vapors

The change in the contact potential difference (CPD) due to ethanol vapor adsorption by a-Si:H/c-Si structure is measured by Kelvin’s method. The measurements are carried out in dry nitrogen ambient and temperature in the interval 20–100 °C. Two types of electrically active adsorption are established—reversible and nonreversible. The reversible ethanol vapor adsorption onto the a-Si:H surface creates positively charged states at 1.1 eV above the Fermi level. The obtained results show that the a-Si:H/c-Si structure can be used for fabrication of alcohol vapor sensors such as open gate field effect transistors (FET).