Massive Seebeck Coefficient of Si/SiO2 Substrate-Supported Graphene Thin Film
AbstractGraphene 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.