Vanadium Pentoxide Alloyed with Graphite for Thin-Film Thermal Sensors

TitleVanadium Pentoxide Alloyed with Graphite for Thin-Film Thermal Sensors
Publication TypeJournal Article
Year of Publication2016
AuthorsBianchi C, Ferreira LM, Loureiro J, Rodrigues A, Duarte P, Baptista AC, Ferreira IM
JournalJournal of Electronic Materials
KeywordsCarrier concentration, Electrical conductivity, Graphite, Graphite powder, Infrared wavelengths, Temperature sensors, Thermal evaporation, Thermal evaporation technique, Thermal sensors, Thermoelectric, Thin films, Vanadium, Vanadium compounds, Vanadium pentoxide, Variable weight

The thermoelectric (TE) properties of vanadium pentoxide (V2O5) alloyed with graphite (G) were studied as a function of its incorporation percentage. Variable weight percentages of graphite powder (0–50%) were added to V2O5 powder and their mixtures were evaporated by a thermal evaporation technique to form thin films with a thickness in the range of 30–80 nm. In the infrared wavelength region, the transmittance of the obtained films increased as the G percentage was increased, while in the visible range, it decreased with G up to 10%. The TE properties were improved when G was in the range of 10–30%, while it decreased for the other percentages: Seebeck coefficient (S) changed from 0.6 mV/K to 0.9 mV/K and was zero with a G of 50%; the electrical conductivity varied slightly from 5 (Ωm)−1 to 0.7 (Ωm)−1 while the mobility improved from 0.07 cm2/V s to 1.5 cm2/V s and the respective carrier concentration was reduced, from 1 × 1018 cm−3 to 4 × 1016 cm−3. These films were applied as temperature sensors evaluating the thermovoltage as a function of thermal gradient between two electrodes, in which one was maintained at room temperature. © 2016, The Minerals, Metals & Materials Society.