Enhanced thermopower of graphene films with oxygen plasma treatment
Tay, Yee Yan
Hng, Huey Hoon
Ajayan, Pulickel M.
Date of Issue2011
School of Materials Science and Engineering
In this work, we show that the maximum thermopower of few layers graphene (FLG) films could be greatly enhanced up to ∼700 μV/K after oxygen plasma treatment. The electrical conductivities of these plasma treated FLG films remain high, for example, ∼104 S/m, which results in power factors as high as ∼4.5 x 10-3 W K-2 m-1. In comparison, the pristine FLG films show a maximum thermopower of ∼80 μV/K with an electrical conductivity of ∼5 x 104 S/m. The proposed mechanism is due to generation of local disordered carbon that opens the band gap. Measured thermopowers of single-layer graphene (SLG) films and reduced graphene oxide (rGO) films were in the range of -40 to 50 and -10 to 20 μV/K, respectively. However, such oxygen plasma treatment is not suitable for SLG and rGO films. The SLG films were easily destroyed during the treatment while the electrical conductivity of rGO films is too low, which makes FLG films unique for possible TE applications.
© 2011 American Chemical Society. This is the author created version of a work that has been peer reviewed and accepted for publication by ACS Nano, American Chemical Society. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [DOI: http://dx.doi.org/10.1021/nn2001849 ]