title: Tuning thermoelectric properties of graphene/boron nitride heterostructures.
abstract: Using density functional theory combined with a Green's function scattering approach, we examine the thermoelectric properties of hetero-nanoribbons formed from alternating lengths of graphene and boron nitride. In such structures, the boron nitride acts as a tunnel barrier, which weakly couples states in the graphene, to form mini-bands. In un-doped nanoribbons, the mini bands are symmetrically positioned relative to the Fermi energy and do not enhance thermoelectric performance significantly. In contrast, when the ribbons are doped by electron donating or electron accepting adsorbates, the thermopower S and electronic figure of merit are enhanced and either positive or negative thermopowers can be obtained. In the most favourable case, doping with the electron donor tetrathiafulvalene increases the room-temperature thermopower to -284 μv K(-1) and doping by the electron acceptor tetracyanoethylene increases S to 210 μv K(-1). After including both electron and phonon contributions to the thermal conductance, figures of merit ZT up to of order 0.9 are obtained.
authors.affiliation: College of Computer Science and Mathematics, Al-Qadisiyah University, Diwaniyah, Iraq. Department of Physics, Lancaster University, Lancaster LA1 4YB, UK. Quantum Technology Centre, Department of Physics, Lancaster University, LA1 4YB Lancaster, UK. College of Basic Education, Sumer University, Al-Refayee, Thi-Qar, Iraq.
authors.forename: Laith A
authors.initials: LA
authors.lastname: Algharagholy
authors.forename: Qusiy
authors.initials: Q
authors.lastname: Al-Galiby
authors.forename: Haider A
authors.initials: HA
authors.lastname: Marhoon
authors.forename: Hatef
authors.initials: H
authors.lastname: Sadeghi
authors.forename: Hayder M
authors.initials: HM
authors.lastname: Abduljalil
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Lambert