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Research output: Contribution to Journal/Magazine › Letter › peer-review
Research output: Contribution to Journal/Magazine › Letter › peer-review
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TY - JOUR
T1 - Geometrically Enhanced Thermoelectric Effects in Graphene Nanoconstrictions
AU - Harzgeim, Achim
AU - Spiece, Jean
AU - Evangeli, Charalambos
AU - McCann, Edward
AU - Falko, Vladimir
AU - Sheng, Yuewen
AU - Warner, Jamie H.
AU - Briggs, G. Andrew D.
AU - Mol, Jan A.
AU - Gehring, Pascal
AU - Kolosov, Oleg Victor
PY - 2018
Y1 - 2018
N2 - 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.
AB - 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.
KW - SThM
KW - Scanning thermal microscopy
KW - scanning thermal gate microscopy
KW - graphene
KW - 2D materials
KW - two-dimensional materials
KW - themoelectrics
KW - nanoscale heat transport
KW - Scanning probe microscopy
U2 - 10.1021/acs.nanolett.8b03406
DO - 10.1021/acs.nanolett.8b03406
M3 - Letter
VL - 18
SP - 7719
EP - 7725
JO - Nano Letters
JF - Nano Letters
SN - 1530-6984
IS - 12
ER -