• Baptista, Ana Catarina
• Ferreira, L. M.
• Ferreira, Isabel
• Bianchi, C.
• Rodrigues, A.
• Duarte, P.
• Loureiro, J.

Abstract

<p>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 (Omega m)(-1) to 0.7 (Omega m)(-1) while the mobility improved from 0.07 cm(2)/V s to 1.5 cm(2)/V s and the respective carrier concentration was reduced, from 1 x 10(18) cm(-3) to 4 x 10(16) 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.</p>

Topics

• mobility
• thin film
• electrical conductivity
• evaporation
• vanadium