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Influence of excitation energy on microscopic quantum pathways for ultrafast charge transfer in van der Waals heterostructures

Niklas Hofmann1, Johannes Gradl1, Leonard Weigl1, Stiven Forti2,3, Camilla Coletti2,3, and Isabella Gierz1,*

  • *Contact author: isabella.gierz@ur.de
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Phys. Rev. Research 8, 033033 – Published 9 July, 2026

DOI: https://doi.org/10.1103/qx7q-s6f4

Abstract

Efficient charge separation in van der Waals (vdW) heterostructures is crucial for optimizing light harvesting and detection applications. However, precise control over the microscopic pathways governing ultrafast charge transfer remains an open challenge. These pathways are intrinsically linked to charge transfer states with strongly delocalized wave functions that appear at various momenta in the Brillouin zone. Here, we use time- and angle-resolved photoemission spectroscopy to investigate the possibility of steering carriers through specific charge transfer states in a prototypical WS2-graphene heterostructure. By selectively exciting electron-hole pairs at the K point (A-exciton resonance) and close to the Q point (C-exciton resonance) of WS2 with different pump photon energies, we find that charge separation is faster at higher excitation energies. This behavior is attributed to the fact that absorption at the C-exciton resonance generates electron-hole populations at energies well above the direct band gap. The resulting elevated carrier temperatures open an additional, highly efficient charge-transfer channel for holes in the WS2 valence band, leading to an overall acceleration of interlayer hole transfer for C-exciton excitation. The microscopic insights gained in this work can be leveraged to optimize the performance of vdW heterostructures in optoelectronic devices.

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References (43)

  1. A. K. Geim and I. V. Grigorieva, Van der Waals heterostructures, Nature (London) 499, 419 (2013).
  2. K. S. Novoselov, A. Mishchenko, A. Carvalho, and A. H. Castro Neto, 2D materials and van der Waals heterostructures, Science 353, aac9439 (2016).
  3. C. Jin, E. Y. Ma, O. Karni, E. C. Regan, F. Wang, and T. F. Heinz, Ultrafast dynamics in van der Waals heterostructures, Nat. Nanotechnol. 13, 994 (2018).
  4. J. He, N. Kumar, M. Z. Bellus, H. Y. Chiu, D. He, Y. Wang, and H. Zhao, Electron transfer and coupling in graphene-tungsten disulfide van der Waals heterostructures, Nat. Commun. 5, 5622 (2014).
  5. M. Massicotte, P. Schmidt, F. Vialla, K. G. Schädler, A. Reserbat-Plantey, K. Watanabe, T. Taniguchi, K. J. Tielrooij, and F. H. Koppens, Picosecond photoresponse in van der Waals heterostructures, Nat. Nanotechnol. 11, 42 (2016).
  6. J. He, D. He, Y. Wang, and H. Zhao, Probing effect of electric field on photocarrier transfer in graphene-WS2 van der Waals heterostructures, Opt. Express 25, 1949 (2017).
  7. Z. Ji, H. Hong, J. Zhang, Q. Zhang, W. Huang, T. Cao, R. Qiao, C. Liu, J. Liang, C. Jin, L. Jiao, K. Shi, S. Meng, and K. Liu, Robust stacking-independent ultrafast charge transfer in MoS2/WS2 bilayers, ACS Nano 11, 12020 (2017).
  8. Z. Song, H. Zhu, W. Shi, D. Sun, and S. Ruan, Ultrafast charge transfer in graphene-WS2 van der Waals heterostructures, Optik 174, 62 (2018).
  9. L. Yuan, T. F. Chung, A. Kuc, Y. Wan, Y. Xu, Y. P. Chen, T. Heine, and L. Huang, Photocarrier generation from interlayer charge-transfer transitions in WS2-graphene heterostructures, Sci. Adv. 4, e1700324 (2018).
  10. S. Fu, I. du Fossé, X. Jia, J. Xu, X. Yu, H. Zhang, W. Zheng, S. Krasel, Z. Chen, Z. M. Wang, K. J. Tielrooij, M. Bonn, A. J. Houtepen, and H. I. Wang, Long-lived charge separation following pump-wavelength–dependent ultrafast charge transfer in graphene/WS2 heterostructures, Sci. Adv. 7, eabd9061 (2021).
  11. Q. Zheng, W. A. Saidi, Y. Xie, Z. Lan, O. V. Prezhdo, H. Petek, and J. Zhao, Phonon-assisted ultrafast charge transfer at van der Waals heterostructure interface, Nano Lett. 17, 6435 (2017).
  12. J. Liu, X. Zhang, and G. Lu, Auger processes and excited state dynamics in WS2/graphene heterostructures: A first-principles perspective, J. Phys. Chem. Lett. 13, 7371 (2022).
  13. N. Hofmann, L. Weigl, J. Gradl, N. Mishra, G. Orlandini, S. Forti, C. Coletti, S. Latini, L. Xian, A. Rubio, D. Perez Paredes, R. Perea Causin, S. Brem, E. Malic, and I. Gierz, Link between interlayer hybridization and ultrafast charge transfer in WS2-graphene heterostructures, 2D Mater. 10, 035025 (2023).
  14. H. Wang, J. Bang, Y. Sun, L. Liang, D. West, V. Meunier, and S. Zhang, The role of collective motion in the ultrafast charge transfer in van der Waals heterostructures, Nat. Commun. 7, 11504 (2016).
  15. R. Long and O. V. Prezhdo, Quantum coherence facilitates efficient charge separation at a MoS2/MoSe2 van der Waals junction, Nano Lett. 16, 1996 (2016).
  16. L. Li, R. Long, and O. V. Prezhdo, Charge separation and recombination in two-dimensional MoS2/WS2: Time-domain ab initio modeling, Chem. Mater. 29, 2466 (2017).
  17. Y. Liu, J. Zhang, S. Meng, C. Yam, and T. Frauenheim, Electric field tunable ultrafast interlayer charge transfer in graphene/WS2 heterostructure, Nano Lett. 21, 4403 (2021).
  18. R. Krause, S. Aeschlimann, M. Ch, M. Chavez-Cervantes, R. Perea-Causin, S. Brem, E. Malic, S. Forti, F. Fabbri, C. Coletti, and I. Gierz, Microscopic understanding of ultrafast charge transfer in van-der-Waals heterostructures, Phys. Rev. Lett. 127, 276401 (2021).
  19. N. Hofmann, A. Steinhoff, R. Krause, N. Mishra, G. Orlandini, S. Forti, C. Coletti, T. O. Wehling, and I. Gierz, k-resolved ultrafast light-induced band renormalization in monolayer WS2 on graphene, Nano Lett. 25, 1214 (2025).
  20. C. Riedl, C. Coletti, T. Iwasaki, A. A. Zakharov, and U. Starke, Quasi-free-standing epitaxial graphene on SiC obtained by hydrogen intercalation, Phys. Rev. Lett. 103, 246804 (2009).
  21. A. Rossi, H. Büch, C. Di Rienzo, V. Miseikis, D. Convertino, A. Al-Temimy, V. Voliani, M. Gemmi, V. Piazza, and C. Coletti, Scalable synthesis of WS2 on graphene and h-BN: An all-2D platform for light-matter transduction, 2D Mater. 3, 031013 (2016).
  22. S. Forti, A. Rossi, H. Büch, T. Cavallucci, F. Bisio, A. Sala, T. O. Menteş, A. Locatelli, M. Magnozzi, M. Canepa, K. Müller, S. Link, U. Starke, V. Tozzini, and C. Coletti, Electronic properties of single-layer tungsten disulfide on epitaxial graphene on silicon carbide, Nanoscale 9, 16412 (2017).
  23. H. Zeng, G. B. Liu, J. Dai, Y. Yan, B. Zhu, R. He, L. Xie, S. Xu, X. Chen, W. Yao, and X. Cui, Optical signature of symmetry variations and spin-valley coupling in atomically thin tungsten dichalcogenides, Sci. Rep. 3, 1608 (2013).
  24. P. R. Wallace, The band theory of graphite, Phys. Rev. 71, 622 (1947).
  25. M. Magnozzi, M. Ferrera, G. Piccinini, S. Pace, S. Forti, F. Fabbri, C. Coletti, F. Bisio, and M. Canepa, Optical dielectric function of two-dimensional WS2 on epitaxial graphene, 2D Mater. 7, 025024 (2020).
  26. S. Aeschlimann, A. Rossi, M. Chávez-Cervantes, R. Krause, B. Arnoldi, B. Stadtmüller, M. Aeschlimann, S. Forti, F. Fabbri, C. Coletti, and I. Gierz, Direct evidence for efficient ultrafast charge separation in epitaxial WS2/graphene heterostructures, Sci. Adv. 6, eaay0761 (2020).
  27. M. M. Ugeda, A. J. Bradley, S. F. Shi, F. H. Da Jornada, Y. Zhang, D. Y. Qiu, W. Ruan, S. K. Mo, Z. Hussain, Z. X. Shen, F. Wang, S. G. Louie, and M. F. Crommie, Giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor, Nat. Mater. 13, 1091 (2014).
  28. A. Chernikov, C. Ruppert, H. M. Hill, A. F. Rigosi, and T. F. Heinz, Population inversion and giant bandgap renormalization in atomically thin WS2 layers, Nat. Photon. 9, 466 (2015).
  29. S. Ulstrup, A. G. Čabo, J. A. Miwa, J. M. Riley, S. S. Grønborg, J. C. Johannsen, C. Cacho, O. Alexander, R. T. Chapman, E. Springate, M. Bianchi, M. Dendzik, J. V. Lauritsen, P. D. King, and P. Hofmann, Ultrafast band structure control of a two-dimensional heterostructure, ACS Nano 10, 6315 (2016).
  30. E. A. Pogna, M. Marsili, D. De Fazio, S. Dal Conte, C. Manzoni, D. Sangalli, D. Yoon, A. Lombardo, A. C. Ferrari, A. Marini, G. Cerullo, and D. Prezzi, Photo-induced bandgap renormalization governs the ultrafast response of single-layer MoS2, ACS Nano 10, 1182 (2016).
  31. P. D. Cunningham, A. T. Hanbicki, K. M. McCreary, and B. T. Jonker, Photoinduced bandgap renormalization and exciton binding energy reduction in WS2, ACS Nano 11, 12601 (2017).
  32. Y. Lin, Y. H. Chan, W. Lee, L. S. Lu, Z. Li, W. H. Chang, C. K. Shih, R. A. Kaindl, S. G. Louie, and A. Lanzara, Exciton-driven renormalization of quasiparticle band structure in monolayer MoS2, Phys. Rev. B 106, L081117 (2022).
  33. R. Wallauer, J. Reimann, N. Armbrust, J. Güdde, and U. Höfer, Intervalley scattering in MoS2 imaged by two-photon photoemission with a high-harmonic probe, Appl. Phys. Lett. 109, 162102 (2016).
  34. R. Bertoni, C. W. Nicholson, L. Waldecker, H. Hübener, C. Monney, U. De Giovannini, M. Puppin, M. Hoesch, E. Springate, R. T. Chapman, C. Cacho, M. Wolf, A. Rubio, and R. Ernstorfer, Generation and evolution of spin-, valley-, and layer-polarized excited carriers in inversion-symmetric WSe2, Phys. Rev. Lett. 117, 277201 (2016).
  35. S. Dong, M. Puppin, T. Pincelli, S. Beaulieu, D. Christiansen, H. Hübener, C. W. Nicholson, R. P. Xian, M. Dendzik, Y. Deng, Y. W. Windsor, M. Selig, E. Malic, A. Rubio, A. Knorr, M. Wolf, L. Rettig, and R. Ernstorfer, Direct measurement of key exciton properties: Energy, dynamics, and spatial distribution of the wave function, Nat. Sci. 1, e10010 (2021).
  36. R. Wallauer, R. Perea-Causin, L. Münster, S. Zajusch, S. Brem, J. Güdde, K. Tanimura, K. Q. Lin, R. Huber, E. Malic, and U. Höfer, Momentum-resolved observation of exciton formation dynamics in monolayer WS2, Nano Lett. 21, 5867 (2021).
  37. J. P. Bange, P. Werner, D. Schmitt, W. Bennecke, G. Meneghini, A. A. AlMutairi, M. Merboldt, K. Watanabe, T. Taniguchi, S. Steil, D. Steil, R. T. Weitz, S. Hofmann, G. S. Jansen, S. Brem, E. Malic, M. Reutzel, and S. Mathias, Ultrafast dynamics of bright and dark excitons in monolayer WSe2 and heterobilayer WSe2/MoS2, 2D Mater. 10, 035039 (2023).
  38. A. Steinhoff, M. Florian, M. Rösner, G. Schönhoff, T. O. Wehling, and F. Jahnke, Exciton fission in monolayer transition metal dichalcogenide semiconductors, Nat. Commun. 8, 1166 (2017).
  39. T. Siday, F. Sandner, S. Brem, M. Zizlsperger, R. Perea-Causin, F. Schiegl, S. Nerreter, M. Plankl, P. Merkl, F. Mooshammer, M. A. Huber, E. Malic, and R. Huber, Ultrafast nanoscopy of high-density exciton phases in WSe2, Nano Lett. 22, 2561 (2022).
  40. M. Dendzik et al., Observation of an excitonic Mott transition through ultrafast core-cum-conduction photoemission spectroscopy, Phys. Rev. Lett. 125, 096401 (2020).
  41. S. Dong et al., Observation of ultrafast interfacial Meitner-Auger energy transfer in a van der Waals heterostructure, Nat. Commun. 14, 5057 (2023).
  42. D. Tebbe, M. Schütte, K. Watanabe, T. Taniguchi, C. Stampfer, B. Beschoten, and L. Waldecker, Distance dependence of the energy transfer mechanism in WS2-graphene heterostructures, Phys. Rev. Lett. 132, 196902 (2024).
  43. D. Erben, A. Steinhoff, M. Lorke, and F. Jahnke, Optical nonlinearities in the excited carrier density of atomically thin transition metal dichalcogenides, Phys. Rev. B 106, 045409 (2022).

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Phys. Rev. Research 8, 033033– Published 9 July, 2026
  • Received 3 September 2025
  • Accepted 27 May 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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