Semiconductor to metallic transition of Bismuth Telluride with incorporation of Graphene- Its enhanced thermoelectric properties

Abstract

Now-a-days nanostructures are being used widely in the fields of electronics. Herein we report a semiconductor to metallic transition of bismuth telluride $(\mathrm{Bi}_{2}\mathrm{Te}_{3})$ by the addition of graphene with enhanced thermoelectric performance. Hydrothermal process has been employed for the synthesis of $\mathrm{Bi}_{2}\mathrm{Te}_{3}$ and $\mathrm{Bi}_{2}\mathrm{Te}_{3}$ - graphene nanocomposites. Structural characterization of the prepared samples has been carried out by X-Ray diffraction (XRD). Electrical characterization shows that there is an increase in the electrical conductivity with the addition of graphene. Interestingly the thermoelectric power increases with the addition of graphene content, which further increases the power factor. The charge carrier mobility and carrier concentration has been evaluated which shows that the increase in the mobility is key factor in the increases of electrical conductivity. The thermal conductivity shows a slight increase in the value with the addition of graphene. The figure of merit (ZT) values as evaluated also shows an increase with the addition of graphene.