Layer-dependent Charge Transfer and inter-layer coupling in WSe2/Graphene Heterostructures
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2025
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| author | Huang, Lan Bobzien, Laric Álvarez, Ángel Labordet Figueroa, Daniel E. Cintron Lu, Li-Syuan Dong, Chengye Robinson, Joshua A. Schuler, Bruno Dimitrievska, Mirjana |
| author_facet | Huang, Lan Bobzien, Laric Álvarez, Ángel Labordet Figueroa, Daniel E. Cintron Lu, Li-Syuan Dong, Chengye Robinson, Joshua A. Schuler, Bruno Dimitrievska, Mirjana |
| contents | Understanding interfacial interactions in two-dimensional (2D) heterostructures is essential for advancing optoelectronic and quantum technologies. We investigate metal-organic chemical vapor deposition (MOCVD)-grown WSe$_2$ films (one to five layers) on graphene/SiC, directly compared to exfoliated WSe$_2$ on SiO$_2$, using Raman and photoluminescence (PL) spectroscopy complemented by atomic force microscopy (AFM). Raman measurements reveal compressive strain and interfacial charge transfer in WSe$_2$/graphene heterostructures, evidenced by blue-shifted phonon modes and the emergence of higher-order interlayer breathing modes absent on SiO$_2$. Concomitant shifts and attenuation of graphene's G and 2D modes with increasing WSe$_2$ thickness indicate progressive p-type doping of graphene, while WSe$_2$ phonon shifts point to n-type doping of the semiconductor, consistent with interfacial electron transfer. PL shows strong quenching for monolayer WSe$_2$ on graphene due to ultrafast charge transfer and F"orster resonance energy transfer (FRET), with partial emission recovery in multilayers relative to SiO$_2$-supported flakes. Exciton behavior differs strongly between substrates: on SiO$_2$, A- and B-exciton energies vary markedly with thickness, whereas on graphene they remain nearly pinned. This stability reflects the combined effects of graphene's strong dielectric screening and charge-transfer-induced free-carrier screening, with strain playing a secondary role. These results establish graphene, unlike SiO$_2$, as an active interfacial partner that stabilizes excitonic states and enables engineering of the optical response of 2D heterostructures. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2509_08340 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Layer-dependent Charge Transfer and inter-layer coupling in WSe2/Graphene Heterostructures Huang, Lan Bobzien, Laric Álvarez, Ángel Labordet Figueroa, Daniel E. Cintron Lu, Li-Syuan Dong, Chengye Robinson, Joshua A. Schuler, Bruno Dimitrievska, Mirjana Materials Science Mesoscale and Nanoscale Physics Understanding interfacial interactions in two-dimensional (2D) heterostructures is essential for advancing optoelectronic and quantum technologies. We investigate metal-organic chemical vapor deposition (MOCVD)-grown WSe$_2$ films (one to five layers) on graphene/SiC, directly compared to exfoliated WSe$_2$ on SiO$_2$, using Raman and photoluminescence (PL) spectroscopy complemented by atomic force microscopy (AFM). Raman measurements reveal compressive strain and interfacial charge transfer in WSe$_2$/graphene heterostructures, evidenced by blue-shifted phonon modes and the emergence of higher-order interlayer breathing modes absent on SiO$_2$. Concomitant shifts and attenuation of graphene's G and 2D modes with increasing WSe$_2$ thickness indicate progressive p-type doping of graphene, while WSe$_2$ phonon shifts point to n-type doping of the semiconductor, consistent with interfacial electron transfer. PL shows strong quenching for monolayer WSe$_2$ on graphene due to ultrafast charge transfer and F"orster resonance energy transfer (FRET), with partial emission recovery in multilayers relative to SiO$_2$-supported flakes. Exciton behavior differs strongly between substrates: on SiO$_2$, A- and B-exciton energies vary markedly with thickness, whereas on graphene they remain nearly pinned. This stability reflects the combined effects of graphene's strong dielectric screening and charge-transfer-induced free-carrier screening, with strain playing a secondary role. These results establish graphene, unlike SiO$_2$, as an active interfacial partner that stabilizes excitonic states and enables engineering of the optical response of 2D heterostructures. |
| title | Layer-dependent Charge Transfer and inter-layer coupling in WSe2/Graphene Heterostructures |
| topic | Materials Science Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2509.08340 |