A team led by Dr. Wei-Li Lee, and Dr. Ting-Kuo Lee has demonstrated for the first time the “field-effect thermoelectricity” in a bilayer graphene device
In a research project on dual-gated bilayer graphene devices led by Dr. Wei-Li Lee and Dr. Ting-Kuo Lee, the “field-effect thermoelectricity” has been demonstrated for the first time. When applying a perpendicular electric field (D) on a bilayer graphene, the thermoelectric power (TEP) can be amplified more than 4 folds while the carrier density remains the same. The value of TEP is comparable to or exceeding several known low temperature thermoelectric materials. The physical mechanism is rooted in the band-gap opening due to the inversion symmetry breaking by D, which largely increases the band curvature near the band edges. On the other hand, its polarity can be readily tuned by the gate voltage to be either electron-type or hole-type. Our results open up a new possibility in thermoelectric application using graphene-based device. Complete data and analysis have been published in Physical Review Letters (PRL 107, 186602 (2011)).
Journal Links: http://prl.aps.org/abstract/PRL/v107/i18/e186602