title: Electrical and Thermal Transport in Coplanar Polycrystalline Graphene-hBN Heterostructures.
abstract: We present a theoretical study of electronic and thermal transport in polycrystalline heterostructures combining graphene (G) and hexagonal boron nitride (hBN) grains of varying size and distribution. By increasing the hBN grain density from a few percent to 100%, the system evolves from a good conductor to an insulator, with the mobility dropping by orders of magnitude and the sheet resistance reaching the MΩ regime. The Seebeck coefficient is suppressed above 40% mixing, while the thermal conductivity of polycrystalline hBN is found to be on the order of 30-120 Wm-1K-1. These results, agreeing with available experimental data, provide guidelines for tuning G-hBN properties in the context of two-dimensional materials engineering. In particular, while we proved that both electrical and thermal properties are largely affected by morphological features (e.g., by the grain size and composition), we find in all cases that nanometer-sized polycrystalline G-hBN heterostructures are not good thermoelectric materials.
authors.affiliation: Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology , Campus UAB, 08193 Barcelona, Spain.
authors.forename: José Eduardo
authors.initials: JE
authors.lastname: Barrios-Vargas
authors.affiliation: Institute of Structural Mechanics, Bauhaus-Universität Weimar , Marienstrasse 15, D-99423 Weimar, Germany.
authors.forename: Bohayra
authors.initials: B
authors.lastname: Mortazavi
authors.affiliation: Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology , Campus UAB, 08193 Barcelona, Spain.
authors.forename: Aron W
authors.initials: AW
authors.lastname: Cummings
authors.affiliation: CINaM - Centre Interdisciplinaire de Nanoscience de Marseille, Aix-Marseille Université , Campus Luminy, Case 913, 13288 Marseille Cedex 9, France.
authors.forename: Rafael
authors.initials: R
authors.lastname: Martinez-Gordillo
authors.affiliation: Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology , Campus UAB, 08193 Barcelona, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Pruneda
authors.affiliation: Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology , Campus UAB, 08193 Barcelona, Spain.|Dipartimento di Fisica, Universit di Cagliari, Cittadella Universitaria , I-09042 Monserrato, Cagliari, Italy.
authors.forename: Luciano
authors.identifier: 0000-0001-5335-4652
authors.initials: L
authors.lastname: Colombo
authors.affiliation: Institute of Structural Mechanics, Bauhaus-Universität Weimar , Marienstrasse 15, D-99423 Weimar, Germany.
authors.forename: Timon
authors.initials: T
authors.lastname: Rabczuk
authors.affiliation: Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology , Campus UAB, 08193 Barcelona, Spain.|ICREA - Institució Catalana de Recerca i Estudis Avançats , 08010 Barcelona, Spain.
authors.forename: Stephan
authors.initials: S
authors.lastname: Roche
keywords: Polycrystalline graphene; boron nitride; chemical vapor deposition; electrical properties; grain boundary; thermal properties; thermoelectrics