Enhancement of thermoelectric figure-of-merit of Graphene upon BN-doping and sample length reduction

Abstract

Using first-principles density functional perturbation theory based calculations of length-dependent lattice thermal conductivity (\k{appa} L ) and using our previously calculated results (Phys Rev B 95 085435 (2017)) of electrical transport, we report results of thermoelectric figure-of-merit (ZT ) of monolayer and bilayer Graphene. We find nearly ten-fold increase in ZT for the graphene sample doped with boron nitride and reduced sample length. We also compare \k{appa} L calculated using the iterative real space method with conventional analytical Callaway-Klemens method and obtain the flexural (ZA) phonon modes to be dominant in thermal transport unlike in the latter method. Our calculations are in good agreement with available experimental data.