INVESTIGATION OF ENHANCED CONDUCTIVITY IN DYE-COATED TIN OXIDE THIN-FILMS USING HALL VOLTAGE MEASUREMENTS

The effects of dye coatings upon the transport properties of tin oxide thin films are studied. Conductivity enhancement factors ranging in magnitude from 2 to 20 were observed in fully characterized films painted with a crystal violet dye derivative. The conductivity enhancement is shown to be due to a combination of mobility and carrier density increase. Both of these effects are attributed lo a reduction in surface scattering within a highly conductive surface layer rather than to more exotic models such as exciton coupling of conduction electrons. Preliminary studies using Langmuir-Blodgett films of the crystal violet dye did not, however, produce an increase in the tin oxide film conductivity.