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Functionalized two-dimensional vdW multijunction MoS2−MoS2/WS2−WS2/WS2−WS2 platform for defect-related carrier dynamics studies

Majvor Mack1, Jia-Yuan Sun2, Bongki Shin3, Stephen Boandoh1,4, Yimo Han3, Jun Lou3, Norbert H. Nickel1, Chien-Chih Lai5, Chih-Wei Luo2,6,7 et al.

Yu-Tsung Tsai1,8,*

  • *Contact author: ytsai@uwyo.edu
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Phys. Rev. Materials 9, 064005 – Published 27 June, 2025

DOI: https://doi.org/10.1103/b339-7j5f

Abstract

Defect engineering plays a critical role in two-dimensional (2D) semiconductor devices, especially for 2D transition-metal dichalcogenides (2D-TMDs) due to their extraordinary optoelectronic properties. However, directly comparing defect-related effects on various devices presents challenges, as it requires multiple growth processes and device fabrication procedures including stacking. Here, we have designed and produced one platform for 2D-TMD multijunction MoS2−MoS2/WS2−WS2/WS2−WS2 on a single flake via chemical vapor deposition (CVD) growth to investigate its photoexcited carrier dynamics. Ultrafast pump-probe transient transmittance measurements at four junctions reveal the defect-related effects on fast and slow relaxation processes and further uncover passivation occurring at the MoS2/WS2 junction, with a longer relaxation time of 25 ps. This work paves the way to establish a paradigm for examining charge-carrier dynamics in functionalized 2D van der Waals multijunctions via CVD growth and a unique microscopic method.

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References (66)

  1. X. Xu, W. Yao, D. Xiao, and T. F. Heinz, Spin and pseudospins in layered transition metal dichalcogenides, Nat. Phys. 10, 343 (2014).
  2. O. Lopez-Sanchez, D. Lembke, M. Kayci, A. Radenovic, and A. Kis, Ultrasensitive photodetectors based on monolayer MoS2, Nat. Nanotechnol. 8, 497 (2013).
  3. T. Scrace, Y. Tsai, B. Barman, L. Schweidenback, A. Petrou, G. Kioseoglou, I. Ozfidan, M. Korkusinski, and P. Hawrylak, Magnetoluminescence and valley polarized state of a two-dimensional electron gas in WS2 monolayers, Nat. Nanotechnol. 10, 603 (2015).
  4. M. Cetina, Ultrafast many-body interferometry of impurities coupled to a Fermi sea, Science 354, 96 (1979).
  5. Y. J. Zhang, T. Oka, R. Suzuki, J. T. Ye, and Y. Iwasa, Electrically switchable chiral light-emitting transistor, Science 344, 725 (1979).
  6. Y. Ma, Y. Dai, M. Guo, C. Niu, Y. Zhu, and B. Huang, Evidence of the existence of magnetism in pristine VX2 monolayers (X=S, Se) and their strain-induced tunable magnetic properties, ACS Nano 6, 1695 (2012).
  7. S. Tongay, Tuning interlayer coupling in large-area heterostructures with CVD-grown MoS2 and WS2 Monolayers, Nano Lett. 14, 3185 (2014).
  8. Y. Gong, Vertical and in-plane heterostructures from WS2/MoS2 monolayers, Nat. Mater. 13, 1135 (2014).
  9. C. Lee, G. Lee, A. M. van der Zande, W. Chen, Y. Li, M. Han, X. Cui, G. Arefe, C. Nuckolls, T. F. Heinz, J. Guo, J. Hone, and P. Kim, Atomically thin p–n junctions with van der Waals heterointerfaces, Nat. Nanotech. 9, 676 (2014).
  10. X. Zhang, Z. Zhang, D. Wu, X. Zhang, X. Zhao, and Z. Zhou, Computational screening of 2D materials and rational design of heterojunctions for water splitting photocatalysts, Small Methods 2, 1700359 (2018).
  11. C. Zhang, Systematic study of electronic structure and band alignment of monolayer transition metal dichalcogenides in van der Waals heterostructures, 2D Mater. 4, 015026 (2016).
  12. Y. Tsai, Z. Chu, Y. Han, C. Chuu, D. Wu, A. Johnson, F. Cheng, M. Chou, D. A. Muller, X. Li, K. Lai, and C. Shih, Tailoring semiconductor lateral multijunctions for giant photoconductivity enhancement, Adv. Mater. 29, 1703680 (2017).
  13. Q. Liang, Q. Zhang, X. Zhao, M. Liu, and A. T. S. Wee, Defect engineering of two-dimensional transition-metal dichalcogenides: Applications, challenges, and opportunities, ACS Nano 15, 2165 (2021).
  14. D. Rhodes, S. H. Chae, R. Ribeiro-Palau, and J. Hone, Disorder in van der Waals heterostructures of 2D materials, Nat. Mater. 18, 541 (2019).
  15. H.-P. Komsa, J. Kotakoski, S. Kurasch, O. Lehtinen, U. Kaiser, and A. V. Krasheninnikov, Two-dimensional transition metal dichalcogenides under electron irradiation: Defect production and doping, Phys. Rev. Lett. 109, 035503 (2012).
  16. E. Mitterreiter, B. Schuler, A. Micevic, D. Hernangómez-Pérez, K. Barthelmi, K. A. Cochrane, J. Kiemle, F. Sigger, J. Klein, E. Wong et al., The role of chalcogen vacancies for atomic defect emission in MoS2, Nat. Commun. 12, 3822 (2021).
  17. M. G. Bianchi, F. Risplendi, M. Re Fiorentin, and G. Cicero, Engineering the electrical and optical properties of WS2 monolayers via defect control, Adv. Sci. 11, 2305162 (2024).
  18. J. Gao, B. Li, J. Tan, P. Chow, T.-M. Lu, and N. Koratkar, Aging of transition metal dichalcogenide monolayers, ACS Nano 10, 2628 (2016).
  19. W. Zhao, J. Ma, P. Sun, K. Zhang, and Y. Yuan, Strong photoluminescence enhancement of MoS2 monolayer via low-power Ar/O2 plasma treatment, Mater. Lett. 235, 129 (2019).
  20. X. Zou, Y. Liu, and B. I. Yakobson, Predicting dislocations and grain boundaries in two-dimensional metal-disulfides from the first principles, Nano Lett. 13, 253 (2013).
  21. Y. Wang, H. Ho, X. Ho, L. Lu, S. Hsieh, S. Huang, H. Chiu, C. Chen, W. Chang, J. D. White, Y. Tang, and W. Woon, Photoluminescence enhancement in WS2 nanosheets passivated with oxygen ions: Implications for selective area doping, ACS Appl. Nano Mater. 4, 11693 (2021).
  22. B. Schuler, J. Lee, C. Kastl, K. A. Cochrane, C. T. Chen, S. Refaely-Abramson, S. Yuan, E. van Veen, R. Roldán et al., How substitutional point defects in two-dimensional WS2 induce charge localization, spin–orbit splitting, and strain, ACS Nano 13, 10520 (2019).
  23. S. Barja, S. Refaely-Abramson, B. Schuler, D. Y. Qiu, A. Pulkin, S. Wickenburg, H. Ryu, M. M. Ugeda, C. Kastl, C. Chen et al., Identifying substitutional oxygen as a prolific point defect in monolayer transition metal dichalcogenides, Nat. Commun. 10, 3382 (2019).
  24. S. Salehi and A. Saffarzadeh, Atomic defect states in monolayers of MoS2 and WS2, Surf. Sci. 651, 215 (2016).
  25. J. Li, W. Su, F. Chen, L. Fu, S. Ding, K. Song, X. Huang, and L. Zhang, Atypical defect-mediated photoluminescence and resonance Raman spectroscopy of monolayer WS2, J. Phys. Chem. C 123, 3900 (2019).
  26. S. Mignuzzi, A. J. Pollard, N. Bonini, B. Brennan, I. S. Gilmore, M. A. Pimenta, D. Richards, and D. Roy, Effect of disorder on Raman scattering of single-layer MoS2, Phys. Rev. B 91, 195411 (2015).
  27. S. Bertolazzi, S. Bonacchi, G. Nan, A. Pershin, D. Beljonne, and P. Samorì, Engineering chemically active defects in monolayer MoS2 transistors via ion-beam irradiation and their healing via vapor deposition of alkanethiols, Adv. Mater. 29, 1606760 (2017).
  28. F. Aryeetey, T. Ignatova, and S. Aravamudhan, Quantification of defects engineered in single layer MoS2, RSC Adv. 10, 22996 (2020).
  29. Y. Chen, S. Huang, X. Ji, K. Adepalli, K. Yin, X. Ling, X. Wang, J. Xue, M. Dresselhaus, J. Kong, and B. Yildiz, Tuning electronic structure of single layer MoS2 through defect and interface engineering, ACS Nano 12, 2569 (2018).
  30. H. Şar, A. Özden, İ. Demiroğlu, C. Sevik, N. K. Perkgoz, and F. Ay, Long-term stability control of CVD-grown monolayer MoS2, Phys. Rapid Res. Lett. 13, 1800687 (2019).
  31. W. Zhou, X. Zou, S. Najmaei, Z. Liu, Y. Shi, J. Kong, J. Lou, P. M. Ajayan, B. I. Yakobson, and J.-C. Idrobo, Intrinsic structural defects in monolayer molybdenum disulfide, Nano Lett. 13, 2615 (2013).
  32. H. Bretscher, Z. Li, J. Xiao, D. Y. Qiu, S. Refaely-Abramson, J. A. Alexander-Webber, A. Tanoh, Y. Fan, G. Delport, C. A. Williams, S. D. Stranks et al., Rational passivation of sulfur vacancy defects in two-dimensional transition metal dichalcogenides, ACS Nano 15, 8780 (2021).
  33. A. L. Elías, Controlled synthesis and transfer of large-area WS2 sheets: From single layer to few layers, ACS Nano 7, 5235 (2013).
  34. D. O. Dumcenco, H. Kobayashi, Z. Liu, Y.-S. Huang, and K. Suenaga, Visualization and quantification of transition metal atomic mixing in Mo1−xWxS2 single layers, Nat. Commun. 4, 1351 (2013).
  35. Z. Lin, M. T. Thee, A. L. Elías, S. Feng, C. Zhou, K. Fujisawa, N. Perea-López, V. Carozo, H. Terrones, and M. Terrones, Facile synthesis of MoS2 and MoxW1−XS2 triangular monolayers, APL Mater. 2, 092514 (2014).
  36. M. Cai, J. Yang, X. Lu, and X. Lu, Layer-by-layer self-assembly strategies of atomically thin two-dimensional nanomaterials: Principles, methods, and functional applications, ACS Appl. Nano Mater. 7, 27940 (2024).
  37. P. V. Pham, T.-H. Mai, S. P. Dash, V. Biju, Y.-L. Chueh, D. Jariwala, and V. Tung, Transfer of 2D films: From imperfection to perfection, ACS Nano 18, 14841 (2024).
  38. F. Chen, X. Jiang, J. Shao, S. Zhao, W. Su, and Y. Li, Multilayered vertical heterostructures comprised of MoS2 and WS2 nanosheets for optoelectronics, ACS Appl. Nano Mater. 4, 9293 (2021).
  39. J. Kang, S. Tongay, J. Zhou, J. Li, and J. Wu, Band offsets and heterostructures of two-dimensional semiconductors, Appl. Phys. Lett. 102, 012111 (2013).
  40. D. Jariwala, A. R. Davoyan, J. Wong, and H. A. Atwater, Van der Waals materials for atomically-thin photovoltaics: Promise and outlook, ACS Photon. 4, 2962 (2017).
  41. Y. Jiang, S. Chen, W. Zheng, B. Zheng, and A. Pan, Interlayer exciton formation, relaxation, and transport in TMD van der Waals heterostructures, Light Sci. Appl. 10, 72 (2021).
  42. X. Hong, J. Kim, S.-F. Shi, Y. Zhang, C. Jin, Y. Sun, S. Tongay, J. Wu, Y. Zhang, and F. Wang, Ultrafast charge transfer in atomically thin MoS2/WS2 heterostructures, Nat. Nanotechnol. 9, 682 (2014).
  43. Y. Wan, J. Huang, C. Chuu, W. Hsu, C. Lee, A. Aljarb, C. Huang, M. Chiu, H. Tang, C. Lin, X. Zhang, C. Wei, S. Li et al., Strain-directed layer-by-layer epitaxy toward van der Waals homo- and heterostructures, ACS Mater. Lett. 3, 442 (2021).
  44. N. Huo, J. Kang, Z. Wei, S. Li, J. Li, and S. Wei, Novel and enhanced optoelectronic performances of multilayer MoS2−WS2 heterostructure transistors, Adv. Funct. Mater. 24, 7025 (2014).
  45. Y. Kim, S. Lee, J. Song, K. Y. Ko, W. J. Woo, S. W. Lee, M. Park, H. Lee, Z. Lee, H. Choi, W. Kim et al., 2D transition metal dichalcogenide heterostructures for p- and n-type photovoltaic self-powered gas sensor, Adv. Funct. Mater. 30, 2003360 (2020).
  46. W. Wu, Q. Zhang, X. Zhou, L. Li, J. Su, F. Wang, and T. Zhai, Self-powered photovoltaic photodetector established on lateral monolayer MoS2−WS2 heterostructures, Nano Energy 51, 45 (2018).
  47. M. Tsai, M. Li, J. R. D. Retamal, K. Lam, Y. Lin, K. Suenaga, L. Chen, G. Liang, L. Li, and J. He, Single atomically sharp lateral monolayer p-n heterojunction solar cells with extraordinarily high power conversion efficiency, Adv. Mater. 29, 1701168 (2017).
  48. J. Ma, J. Pang, J. Yang, W. Xie, X. Kuang, and A. Mao, Prediction of high photoconversion efficiency and photocatalytic water splitting in vertically stacked TMD heterojunctions MX2/WS2 and MX2/MoSe2 (M=Cr, Mo, W; X=S, Se, Te), J. Mater. Chem. A 13, 9312 (2025).
  49. J. D. Fuhr, A. Saúl, and J. O. Sofo, Scanning tunneling microscopy chemical signature of point defects on the MoS2 (0001) surface, Phys. Rev. Lett. 92, 026802 (2004).
  50. J. Lin, S. T. Pantelides, and W. Zhou, Vacancy-induced formation and growth of inversion domains in transition-metal dichalcogenide monolayer, ACS Nano 9, 5189 (2015).
  51. R. Addou, Impurities and electronic property variations of natural MoS2 crystal surfaces, ACS Nano 9, 9124 (2015).
  52. Z. Sun, A. Martinez, and F. Wang, Optical modulators with 2D layered materials, Nat. Photon. 10, 227 (2016).
  53. M. Amani, Near-unity photoluminescence quantum yield in MoS2, Science 350, 1065 (2015).
  54. S. Boandoh, F. Hsiao, B. Shin, M. Mack, L. P. Grote, R. Wang, Y. Han, J. Lou, N. Koch, N. H. Nickel, C. Luo, and Y. Tsai, Ultrafast pump–probe microscopy on 2D transition metal dichalcogenides, Adv Photon. Res. 3, 2200046 (2022).
  55. J. Lei, Y. Xie, A. Kutana, K. V. Bets, and B. I. Yakobson, Salt-assisted MoS2 growth: Molecular mechanisms from the first principles, J. Am. Chem. Soc. 144, 7497 (2022).
  56. L. Seravalli and M. Bosi, A review on chemical vapour deposition of two-dimensional MoS2 flakes, Materials 14, 7590 (2021).
  57. See Supplemental Material at http://link.aps.org/supplemental/10.1103/b339-7j5f for micro-Raman/PL characterization and annular dark-field scanning transmission electron microscopy (ADF-STEM) image of the sample, as well as the instrumental response function of pump-probe spectroscopy.
  58. A. M. Zande, P. Y. Huang, D. A. Chenet, T. C. Berkelbach, Y. You, G.-H. Lee, T. F. Heinz, D. R. Reichman, D. A. Muller, and J. C. Hone, Grains and grain boundaries in highly crystalline monolayer molybdenum disulphide, Nat. Mater. 12, 554 (2013).
  59. T. Huang, X. Cong, S. Wu, K. Lin, X. Yao, Y. He, J. Wu, Y. Bao, S. Huang, X. Wang, P. Tan, B. Ren et al., Probing the edge-related properties of atomically thin MoS2 at nanoscale, Nat. Commun. 10, 5544 (2019).
  60. H. Liu, T. Yang, Y. Tatsumi, Y. Zhang, B. Dong, H. Guo, Z. Zhang, Y. Kumamoto, M. Li, L. Li, R. Saito, and S. Kawata, Deep-ultraviolet Raman scattering spectroscopy of monolayer WS2, Sci. Rep. 8, 11398 (2018).
  61. H. Wang, C. Zhang, and F. Rana, Ultrafast dynamics of defect-assisted electron–hole recombination in monolayer MoS2, Nano Lett. 15, 339 (2015).
  62. T. Goswami, R. Rani, K. S. Hazra, and H. N. Ghosh, Ultrafast carrier dynamics of the exciton and trion in MoS2 monolayers followed by dissociation dynamics in Au@MoS2 2D heterointerfaces, J. Phys. Chem. Lett. 10, 3057 (2019).
  63. J. Shah, Ultrafast Spectroscopy of Semiconductors and Semiconductor Nanostructures (Springer, Berlin, 1999), Vol. 115.
  64. J. M. Dawlaty, S. Shivaraman, J. Strait, P. George, M. Chandrashekhar, F. Rana, M. G. Spencer, D. Veksler, and Y. Chen, Measurement of the optical absorption spectra of epitaxial graphene from terahertz to visible, Appl. Phys. Lett. 93, 131905 (2008).
  65. A. Senkić, A. Supina, M. Akturk, C. Gadermaier, M. Maiuri, G. Cerullo, and N. Vujičić, Microscopic investigation of intrinsic defects in CVD grown MoS2 monolayers, Nanotechnology 34, 475705 (2023).
  66. Q. Cui, Robust and high photoluminescence in WS2 monolayer through in situ defect engineering, Adv. Funct. Mater. 31, 2105339 (2021).

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Phys. Rev. Materials 9, 064005– Published 27 June, 2025
  • Received 23 January 2025
  • Accepted 6 June 2025
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