Enhanced thermoelectric performance of twisted bilayer graphene nanoribbons junction

We investigate the electron transport and thermoelectric property of twisted bilayer graphene nanoribbon junction (TBGNRJ) in 0 degrees, 21.8 degrees, 38.2 degrees and 60 degrees rotation angles by first principles calculation with Landauer-Buttiker and Boltzmann theories. It is found that TBGNRJs exhibit a strong reduction of thermal conductance compared with the single graphene nanoribbon (GNR) and negative differential resistance (NDR) in 21.8 degrees and 38.2 degrees rotation angles under +/- 0.2 V bias voltage. More importantly, three peak ZT values of 2.0, 2.7 and 6.1 can be achieved in the 21.8 degrees rotation angle at 300 K. The outstanding ZT values of TBGNRJs are interpreted as the combination of the reduced thermal conductivity and enhanced electrical conductivity at optimized angles. (c) 2019 Elsevier Ltd. All rights reserved.