Photo-Thermoelectric Effect at a Graphene Interface Junction

• Published in: Nano letters 2010-02, Vol.10 (2), p.562-566
• Main Authors: Xu, Xiaodong, Gabor, Nathaniel M, Alden, Jonathan S, van der Zande, Arend M, McEuen, Paul L
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic structure of nanoscale materials : clusters, nanoparticles, nanotubes, and nanocrystals; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Materials science; Physics; Specific materials; Thermal properties of condensed matter; Thermal properties of small particles, nanocrystals, nanotubes
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl903451y

We investigate the optoelectronic response of a graphene single-bilayer interface junction using photocurrent (PC) microscopy. We measure the polarity and amplitude of the PC while varying the Fermi level by tuning a gate voltage. These measurements show that the generation of PC is by a photothermoelectric effect. The PC displays a factor of ∼10 increase at the cryogenic temperature as compared to room temperature. Assuming the thermoelectric power has a linear dependence on the temperature, the inferred graphene thermal conductivity from temperature dependent measurements has a T 1.5 dependence below ∼100 K, which agrees with recent theoretical predictions.