Optimization of Thermoelectric Performance of Graphene Nanoribbons by Controlling Nano Structure

Abstract

Effects of edge disorder on thermoelectric performance of graphene nanoribbons (GNRs) were investigated through computational simulations based on the non-equilibrium Green's function method combined with the tight-binding approximation. We found that the thermoelectric power factor PF can be optimized by adjusting the ribbon length, L, of GNRs with edge disorder concentration C_d. For example, at room temperature, PF of zigzag-edged GNRs at the Fermi energy shows a maximum value of 33 mW/(m K²) when C_d = 10% and L = 210 nm. Both the maximum PF and optimum L decrease with increasing C_d. The maximum PF is theoretically explained in terms of the crossover from the ballistic transport regime to the Anderson's localization regime.