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Massive Seebeck Coefficient of Si/SiO2 Substrate-Supported Graphene Thin Film
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  • Himal Wijekoon,
  • Lahiru Kulanga,
  • Athula Wijayasinghe,
  • Deepal Subasinghe
Himal Wijekoon
Postgraduate Institute of Science, University of Peradeniya, National Institute of Fundamental Studies
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Lahiru Kulanga
Postgraduate Institute of Science, University of Peradeniya, National Institute of Fundamental Studies
Athula Wijayasinghe
National Institute of Fundamental Studies
Deepal Subasinghe
National Institute of Fundamental Studies

Abstract

Graphene has been used in applications in many fields due to its outstanding electronic, thermal and mechanical properties, since its discovery in 2004. However, having a higher thermal conductivity and lacking of band gap makes graphene unsuitable to use in thermoelectric generators. Several research works have been conducted to reduce the thermal conductivity and introduce a band gap to graphene. However, despite having few theoretically developed studies, experimental work on the thermoelectric properties of graphene are scarce. We deposited few graphene layers on a Si/SiO2 substrate using an ultra-high vacuum thermal evaporator which is a novel and unreported technique to synthesis graphene thin film. Thermally reduced graphene oxide synthesized using a modified Hummers method was used as the source material for thermal evaporation. The formation of the thin film was studied by X-ray diffraction and UV-Visible spectrometry. The measured Seebeck coefficient of the thin film attained a maximum value of 35.04 mV K-1 at room temperature. This is one of the largest Seebeck coefficients reported ever.