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

TL;DR

This paper demonstrates a significant enhancement in the thermoelectric figure-of-merit (ZT) of graphene through BN-doping and sample length reduction, supported by first-principles calculations and comparison with experimental data.

Contribution

It provides a detailed first-principles analysis of how BN-doping and size reduction improve graphene's thermoelectric performance, including thermal conductivity insights.

Findings

ZT increases nearly ten-fold with BN-doping and size reduction

Flexural phonon modes dominate thermal transport in the studied samples

Calculated thermal conductivity aligns well with experimental data

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.