Valcheva, E.Kirilov, K.Bundaleska, N.Dias, A.Felizardo, E.Abrashev, M.Bundaleski, N.Teodoro, O. M. N. D.Strunskus, ThKiss’ovski, ZhAlves, L. L.Tatarova, E.2023-07-102023-07-102023-022053-1591PURE: 65459969PURE UUID: 65187168-dde3-4956-9d20-62672751bbbdScopus: 85148011638WOS: 000935625800001ORCID: /0000-0002-3424-2847/work/151385471http://hdl.handle.net/10362/155065Funding Information: The authors would like to thank S. Russev for the SEM images. M A, E V, K K and Zh K thank the European Regional Development Fund within the Operational Programme ‘Science and Education for Smart Growth 2014–2020’ under the Project CoE ‘National center of mechatronics and clean technologies ‘BG05M2OP001-1.001-0008’. Publisher Copyright: © 2023 The Author(s). Published by IOP Publishing Ltd.In this paper, the electrical transport in free-standing graphene and N-graphene sheets fabricated by a microwave plasma-based method is addressed. Temperature-dependent resistivity/conductivity measurements are performed on the graphene/N-graphene sheets compressed in pellets. Different measurement configurations reveal directional dependence of current flow—the room-temperature conductivity longitudinal to the pellet’s plane is an order of magnitude higher than the transversal one, due to the preferential orientation of graphene sheets in the pellets. SEM imaging confirms that the graphene sheets are mostly oriented parallel to the pellet’s plane and stacked in agglomerates. The high longitudinal electrical conductivity with values on the order of 103 S/m should be noted. Further, the current flow mechanism revealed from resistivity-temperature dependences from 300K down to 10K shows non-metallic behavior manifested with an increasing resistivity with decreasing the temperature d ρ / d T < 0 usually observed for insulating or localized systems. The observed charge transport shows variable range hopping at lower temperatures and thermally activated behaviour at higher temperatures. This allows us to attribute the charge transport mechanism to a partially disordered system in which single graphene sheets are placed predominantly parallel to each other and stacked together.11910864engfree-standing graphene sheetslow temperature conduction mechanismmicrowave plasma-based synthesisN-dopingvariable range hoppingElectronic, Optical and Magnetic MaterialsBiomaterialsSurfaces, Coatings and FilmsPolymers and PlasticsMetals and Alloysjournal article10.1088/2053-1591/acb7cahttps://www.scopus.com/pages/publications/85148011638