Geometrically Enhanced Thermoelectric Effects in Graphene Nanoconstrictions

Harzgeim, Achim and Spiece, Jean and Evangeli, Charalambos and McCann, Edward and Falko, Vladimir and Sheng, Yuewen and Warner, Jamie H. and Briggs, G. Andrew D. and Mol, Jan A. and Gehring, Pascal and Kolosov, Oleg Victor (2018) Geometrically Enhanced Thermoelectric Effects in Graphene Nanoconstrictions. Nano Letters, 18 (12). pp. 7719-7725. ISSN 1530-6984

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Abstract

The influence of nanostructuring and quantum confinement on the thermoelectric properties of materials has been extensively studied. While this has made possible multiple breakthroughs in the achievable figure of merit, classical confinement, and its effect on the local Seebeck coefficient has mostly been neglected, as has the Peltier effect in general due to the complexity of measuring small temperature gradients locally. Here we report that reducing the width of a graphene channel to 100 nm changes the Seebeck coefficient by orders of magnitude. Using a scanning thermal microscope allows us to probe the local temperature of electrically contacted graphene two-terminal devices or to locally heat the sample. We show that constrictions in mono- and bilayer graphene facilitate a spatially correlated gradient in the Seebeck and Peltier coefficient, as evidenced by the pronounced thermovoltage Vth and heating/cooling response ΔTPeltier, respectively. This geometry dependent effect, which has not been reported previously in 2D materials, has important implications for measurements of patterned nanostructures in graphene and points to novel solutions for effective thermal management in electronic graphene devices or concepts for single material thermocouples.

Item Type:
Journal Article
Journal or Publication Title:
Nano Letters
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2200/2210
Subjects:
ID Code:
129225
Deposited By:
Deposited On:
28 Nov 2018 15:10
Refereed?:
Yes
Published?:
Published
Last Modified:
29 Sep 2020 04:39