Edge-oxidation effects on the thermoelectric properties in graphene nanoribbons

The thermal, electrical and thermoelectric properties in edge modified zigzag graphene nanoribbon are analyzed carefully by nonequilibrium Green's function formalism combined with first principles calculation. Epoxy (-O-) and hydroxyl groups (-OH) are considered for the ZGNR edge modification (ZGNR-O and ZGNR-OH). The results show that ZGNR-O and ZGNR-OH both can suppress obviously the phonon transport, leading to low phonon thermal conductance. While ZGNR-O and ZGNR-OH hardly suppress electron transport within the positive energy, which induces one conductance quantum plateau can be observed in ZGNR-O and ZGNR-OH. At the negative energies, ZGNR-O can suppress obviously the electron transport, which induces violent fluctuation of electronic transmissions, leading to high Seebeck coefficient and enhanced thermopower.