Thermopower and hall effect in silicon nitride composites containing thermally reduced graphene and pure graphene nanosheets
Composites consisting of dielectric silicon nitride (SiN) with diverse percentages of different graphene nanoreinforcements, such as graphene nanoplatelets (GNP) - 17 and 21 vol% - and reduced graphene oxide (rGO) sheets - 4 and 7 vol% - displayed thermopower effect. Maximum thermopower was observed...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2016 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/190955 |
| Acceso en línea: | http://hdl.handle.net/10261/190955 |
| Access Level: | acceso abierto |
| Palabra clave: | Graphene Hall effect Nanoclusters N-doping STEM graphene oxide Ceramics Si3N4 thermopower |
| Sumario: | Composites consisting of dielectric silicon nitride (SiN) with diverse percentages of different graphene nanoreinforcements, such as graphene nanoplatelets (GNP) - 17 and 21 vol% - and reduced graphene oxide (rGO) sheets - 4 and 7 vol% - displayed thermopower effect. Maximum thermopower was observed for the rGO containing composites, which reached a peak Seebeck coefficient (S) of -26 μV K at 300 K, whereas GNP composites showed top S of +5 μV K at the same temperature. Hall effect measurements indicated that current carriers were different in both composites, electrons for the rGO/SiN (n-type conductor) and holes for the GNP/SiN materials (p-type conductor) and also having ∼1.4 times higher carrier concentration the first composites. The enhanced thermopower of the rGO/SiN composites is attributed to the particular defective nature of rGO sheets, which presented edge defects and nanometer scale defect clusters as shown by the high resolution transmission electron microscope images - probably associated to both oxygen atoms remaining after GO reduction during spark plasma sintering and N doping from the SiN matrix. |
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