Decoupling thermoelectric coefficients of multilayer graphene by nanomeshing
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| Format: | Preprint |
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2025
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| author | Rahimi, Mehrdad Lubertino, Nunzia Bellelli, Roberto Chen, Linsai Mallet, François Lafarge, Philippe Barraud, Clément Marti, PAscal Chaste, Julien Fournier, Danièle Della Rocca, Maria Luisa |
| author_facet | Rahimi, Mehrdad Lubertino, Nunzia Bellelli, Roberto Chen, Linsai Mallet, François Lafarge, Philippe Barraud, Clément Marti, PAscal Chaste, Julien Fournier, Danièle Della Rocca, Maria Luisa |
| contents | Nanostructuring materials at small scales enables control over their physical properties, revealing behaviors not observed at larger dimensions. This strategy is particularly effective in two-dimensional (2D) materials, where surface effects dominate, and has been applied in the thermoelectric field. Here, we use multilayer graphene (4-6 nm thick) as a test platform to study the effect of nanomeshing on its thermoelectric properties. The nanomesh consists of a hexagonal array of holes, with a measured diameter and neck-width of ~360 nm and ~160 nm, respectively. The multilayer graphene is integrated into field-effect transistor-like devices supported by hexagonal boron nitride (hBN), allowing simultaneous electric and thermoelectric measurements, with nanomeshing applied to only part of the material. We use modulated thermoreflectance to investigate thermal transport in equivalent nanomeshed and pristine graphene flakes, extracting key parameters that affect thermoelectric performance. The nanomesh geometry suppresses thermal transport without significantly impacting charge transport, highlighting the different scattering lengths of phonons and electrons while enhancing the thermopower response. We observe a twofold improvement in the device power factor, PF = S^2 sigma (with S the Seebeck coefficient and sigma the electrical conductivity), at room temperature, along with a nearly threefold reduction in thermal conductivity k. The results show that nanomeshing can significantly improve the thermoelectric performance of multilayer graphene, paving the way for novel energy conversion strategies using 2D materials. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_03436 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Decoupling thermoelectric coefficients of multilayer graphene by nanomeshing Rahimi, Mehrdad Lubertino, Nunzia Bellelli, Roberto Chen, Linsai Mallet, François Lafarge, Philippe Barraud, Clément Marti, PAscal Chaste, Julien Fournier, Danièle Della Rocca, Maria Luisa Mesoscale and Nanoscale Physics Other Condensed Matter Nanostructuring materials at small scales enables control over their physical properties, revealing behaviors not observed at larger dimensions. This strategy is particularly effective in two-dimensional (2D) materials, where surface effects dominate, and has been applied in the thermoelectric field. Here, we use multilayer graphene (4-6 nm thick) as a test platform to study the effect of nanomeshing on its thermoelectric properties. The nanomesh consists of a hexagonal array of holes, with a measured diameter and neck-width of ~360 nm and ~160 nm, respectively. The multilayer graphene is integrated into field-effect transistor-like devices supported by hexagonal boron nitride (hBN), allowing simultaneous electric and thermoelectric measurements, with nanomeshing applied to only part of the material. We use modulated thermoreflectance to investigate thermal transport in equivalent nanomeshed and pristine graphene flakes, extracting key parameters that affect thermoelectric performance. The nanomesh geometry suppresses thermal transport without significantly impacting charge transport, highlighting the different scattering lengths of phonons and electrons while enhancing the thermopower response. We observe a twofold improvement in the device power factor, PF = S^2 sigma (with S the Seebeck coefficient and sigma the electrical conductivity), at room temperature, along with a nearly threefold reduction in thermal conductivity k. The results show that nanomeshing can significantly improve the thermoelectric performance of multilayer graphene, paving the way for novel energy conversion strategies using 2D materials. |
| title | Decoupling thermoelectric coefficients of multilayer graphene by nanomeshing |
| topic | Mesoscale and Nanoscale Physics Other Condensed Matter |
| url | https://arxiv.org/abs/2507.03436 |