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Wafer-scale production of patterned transition metal ditelluride layers for two-dimensional metal–semiconductor contacts at the Schottky–Mott limit

Abstract

A key challenge in the development of two-dimensional (2D) devices is the fabrication of metal–semiconductor junctions with minimal contact resistance and depinned energy levels. An ideal solution for practical applications is to make contacts between 2D van der Waals semiconductors and 2D van der Waals metals. Here we report the wafer-scale production of patterned layers of metallic transition metal ditellurides on different substrates. Our tungsten ditelluride and molybdenum ditelluride layers, which are grown using a tellurization process applied to a precursor transition metal layer, have an electronic performance comparable to that of mechanically exfoliated flakes and can be combined with the 2D semiconductor molybdenum disulfide. The resulting metal–semiconductor junctions are free from significant disorder effects and Fermi-level pinning, and are used to create monolayer molybdenum disulfide field-effect transistors. The Schottky barrier heights of the devices also largely follow the trend of the Schottky–Mott limit.

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Fig. 1: Position-controllable growth of WTe2 atomic layers directly on a SiO2/Si substrate.
Fig. 2: Electro- and magnetotransporting behaviours of WTe2 films.
Fig. 3: Atomically thin FETs composed of the MoS2 channel and WTe2 contact.
Fig. 4: Low SB nature of (W,Mo)Te2 contacts for atomically thin FETs.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

References

  1. 1.

    Sze, S. M. & Ng, K. K. Physics of Semiconductor Devices 3rd edn (Wiley-Interscience, 2007).

  2. 2.

    Liu, W., Sarkar, D., Kang, J. H., Cao, W. & Banerjee, K. Impact of contact on the operation and performance of back-gated monolayer MoS2 field-effect-transistors. ACS Nano 9, 7904–7912 (2015).

    Google Scholar 

  3. 3.

    Liu, Y. Y., Stradins, P. & Wei, S. H. van der Waals metal-semiconductor junction: weak Fermi level pinning enables effective tuning of Schottky barrier. Sci. Adv. 2, e1600069 (2016).

    Google Scholar 

  4. 4.

    Schulman, D. S., Arnold, A. J. & Das, S. Contact engineering for 2D materials and devices. Chem. Soc. Rev. 47, 3037–3058 (2018).

    Google Scholar 

  5. 5.

    Xu, J., Shim, J., Park, J. H. & Lee, S. MXene electrode for the integration of WSe2 and MoS2 field effect transistors. Adv. Funct. Mater. 26, 5328–5334 (2016).

    Google Scholar 

  6. 6.

    Dimoulas, A., Tsipas, P., Sotiropoulos, A. & Evangelou, E. K. Fermi-level pinning and charge neutrality level in germanium. Appl. Phys. Lett. 89, 252110 (2006).

    Google Scholar 

  7. 7.

    Allain, A., Kang, J. H., Banerjee, K. & Kis, A. Electrical contacts to two-dimensional semiconductors. Nat. Mater. 14, 1195–1205 (2015).

    Google Scholar 

  8. 8.

    Liu, Y. et al. Approaching the Schottky–Mott limit in van der Waals metal–semiconductor junctions. Nature 557, 696–700 (2018).

    Google Scholar 

  9. 9.

    Kim, C. et al. Fermi level pinning at electrical metal contacts of monolayer molybdenum dichalcogenides. ACS Nano 11, 1588–1596 (2017).

    Google Scholar 

  10. 10.

    Chuang, H. J. et al. Low-resistance 2D/2D ohmic contacts: a universal approach to high-performance WSe2, MoS2, and MoSe2 transistors. Nano Lett. 16, 1896–1902 (2016).

    Google Scholar 

  11. 11.

    Jeon, J. et al. Epitaxial synthesis of molybdenum carbide and formation of a Mo2C/MoS2 hybrid structure via chemical conversion of molybdenum disulfide. ACS Nano 12, 338–346 (2018).

    Google Scholar 

  12. 12.

    Chee, S. S. et al. Lowering the Schottky barrier height by graphene/Ag electrodes for high-mobility MoS2 field-effect transistors. Adv. Mater. 31, 1804422 (2019).

    Google Scholar 

  13. 13.

    Mahajan, M., Murali, K., Kawatra, N. & Majumdar, K. Gate-controlled large resistance switching driven by charge-density wave in 1T-TaS2/2H-MoS2 heterojunctions. Phys. Rev. Appl. 11, 024031 (2019).

    Google Scholar 

  14. 14.

    Ji, Q. Q. et al. Metallic vanadium disulfide nanosheets as a platform material for multifunctional electrode applications. Nano Lett. 17, 4908–4916 (2017).

    Google Scholar 

  15. 15.

    Leong, W. S. et al. Synthetic lateral metal–semiconductor heterostructures of transition metal disulfides. J. Am. Chem. Soc. 140, 12354–12358 (2018).

    Google Scholar 

  16. 16.

    Shin, H. G. et al. Vertical and in-plane current devices using NbS2/n-MoS2 van der Waals Schottky junction and graphene contact. Nano Lett. 18, 1937–1945 (2018).

    Google Scholar 

  17. 17.

    Dawson, W. G. & Bullett, D. W. Electronic-structure and crystallography of MoTe2 and WTe2. J. Phys. C 20, 6159–6174 (1987).

    Google Scholar 

  18. 18.

    Song, S. et al. Electrically robust single-crystalline WTe2 nanobelts for nanoscale electrical interconnects. Adv. Sci. 6, 1801370 (2019).

    Google Scholar 

  19. 19.

    Komsa, H. P. et al. Two-dimensional transition metal dichalcogenides under electron irradiation: defect production and doping. Phys. Rev. Lett. 109, 035503 (2012).

    Google Scholar 

  20. 20.

    Mleczko, M. J. et al. Contact engineering high-performance n-type MoTe2 transistors. Nano Lett. 19, 6352–6362 (2019).

    Google Scholar 

  21. 21.

    Yun, S. J. et al. Telluriding monolayer MoS2 and WS2 via alkali metal scooter. Nat. Commun. 8, 2163 (2017).

    Google Scholar 

  22. 22.

    Zhou, J. D. et al. Large-area and high-quality 2D transition metal telluride. Adv. Mater. 29, 1603471 (2017).

    Google Scholar 

  23. 23.

    Kim, T. et al. Wafer-scale epitaxial 1T′, 1T′–2H mixed, and 2H phases MoTe2 thin films grown by metal–organic chemical vapor deposition. Adv. Mater. Interfaces 5, 1800439 (2018).

    Google Scholar 

  24. 24.

    de Melo, O. et al. WTe2 Synthesis by tellurization of W precursors using isothermal close space vapor transport annealing. Phys. Status Solidi A 215, 1800425 (2018).

    Google Scholar 

  25. 25.

    Huang, J. H. et al. Large-area 2D layered MoTe2 by physical vapor deposition and solid-phase crystallization in a tellurium-free atmosphere. Adv. Mater. Interfaces 4, 1700157 (2017).

    Google Scholar 

  26. 26.

    Kwak, J. et al. Single-crystalline nanobelts composed of transition metal ditellurides. Adv. Mater. 30, 1707260 (2018).

    Google Scholar 

  27. 27.

    Kim, S. Y., Kwak, J., Ciobanu, C. V. & Kwon, S.-Y. Recent developments in controlled vapor-phase growth of 2D Group 6 transition metal dichalcogenides. Adv. Mater. 31, 1804939 (2019).

    Google Scholar 

  28. 28.

    Lee, C. H. et al. Tungsten ditelluride: a layered semimetal. Sci. Rep. 5, 10013 (2015).

    Google Scholar 

  29. 29.

    Li, J., Cheng, S., Liu, Z. X., Zhang, W. F. & Chang, H. X. Centimeter-scale, large-area, few-layer 1T′-WTe2 films by chemical vapor deposition and its long-term stability in ambient condition. J. Phys. Chem. C 122, 7005–7012 (2018).

    Google Scholar 

  30. 30.

    Zhou, Y. et al. Direct synthesis of large-scale WTe2 thin films with low thermal conductivity. Adv. Funct. Mater. 27, 1605928 (2017).

    Google Scholar 

  31. 31.

    Fei, Z. Y. et al. Edge conduction in monolayer WTe2. Nat. Phys. 13, 677–682 (2017).

    Google Scholar 

  32. 32.

    Asaba, T. et al. Magnetic field enhanced superconductivity in epitaxial thin film WTe2. Sci. Rep. 8, 6520 (2018).

    Google Scholar 

  33. 33.

    Woods, J. M. et al. Suppression of magnetoresistance in thin WTe2 flakes by surface oxidation. ACS Appl. Mater. Interfaces 9, 23175–23180 (2017).

    Google Scholar 

  34. 34.

    Mleczko, M. J. et al. High current density and low thermal conductivity of atomically thin semimetallic WTe2. ACS Nano 10, 7507–7514 (2016).

    Google Scholar 

  35. 35.

    Liu, X. et al. Gate tunable magneto-resistance of ultra-thin WTe2 devices. 2D Mater. 4, 021018 (2017).

    Google Scholar 

  36. 36.

    Song, S. M., Park, J. K., Sul, O. J. & Cho, B. J. Determination of work function of graphene under a metal electrode and its role in contact resistance. Nano Lett. 12, 3887–3892 (2012).

    Google Scholar 

  37. 37.

    Park, H. Y. et al. Extremely low contact resistance on graphene through n-type doping and edge contact design. Adv. Mater. 28, 864–870 (2016).

    Google Scholar 

  38. 38.

    Russo, S., Craciun, M. F., Yamamoto, M., Morpurgo, A. F. & Tarucha, S. Contact resistance in graphene-based devices. Physica E 42, 677–679 (2010).

    Google Scholar 

  39. 39.

    Nagashio, K., Nishimura, T., Kita, K. & Toriumi, A. Contact resistivity and current flow path at metal/graphene contact. Appl. Phys. Lett. 97, 143514 (2010).

    Google Scholar 

  40. 40.

    Gao, M. et al. Tuning the transport behavior of centimeter-scale WTe2 ultrathin films fabricated by pulsed laser deposition. Appl. Phys. Lett. 111, 031906 (2017).

    Google Scholar 

  41. 41.

    Liu, W. L. et al. Effect of aging-induced disorder on the quantum transport properties of few-layer WTe2. 2D Mater. 4, 011011 (2017).

    Google Scholar 

  42. 42.

    Wang, L. et al. Tuning magnetotransport in a compensated semimetal at the atomic scale. Nat. Commun. 6, 8892 (2015).

    Google Scholar 

  43. 43.

    Ye, F. et al. Environmental instability and degradation of single- and few-layer WTe2 nanosheets in ambient conditions. Small 12, 5802–5808 (2016).

    Google Scholar 

  44. 44.

    Yu, L. L. et al. Graphene/MoS2 hybrid technology for large-scale two-dimensional electronics. Nano Lett. 14, 3055–3063 (2014).

    Google Scholar 

  45. 45.

    Bark, H. et al. Large-area niobium disulfide thin films as transparent electrodes for devices based on two-dimensional materials. Nanoscale 10, 1056–1062 (2018).

    Google Scholar 

  46. 46.

    Lu, Q. et al. Experimental investigation of the contact resistance of graphene/MoS2 interface treated with O2 plasma. Superlattice Microstruct. 114, 421–427 (2018).

    Google Scholar 

  47. 47.

    Du, Y. C. et al. MoS2 field-effect transistors with graphene/metal heterocontacts. IEEE Elect. Dev. Lett. 35, 599–601 (2014).

    Google Scholar 

  48. 48.

    Liu, Y. et al. Toward barrier free contact to molybdenum disulfide using graphene electrodes. Nano Lett. 15, 3030–3034 (2015).

    Google Scholar 

  49. 49.

    Leong, W. S. et al. Low resistance metal contacts to MoS2 devices with nickel-etched-graphene electrodes. ACS Nano 9, 869–877 (2015).

    Google Scholar 

  50. 50.

    Kwon, J. et al. Thickness-dependent Schottky barrier height of MoS2 field-effect transistors. Nanoscale 9, 6151–6157 (2017).

    Google Scholar 

  51. 51.

    Dathbun, A. et al. Selectively metallized 2D materials for simple logic devices. ACS Appl. Mater. Interfaces 11, 18571–18579 (2019).

    Google Scholar 

  52. 52.

    Guimaraes, M. H. D. et al. Atomically thin ohmic edge contacts between two-dimensional materials. ACS Nano 10, 6392–6399 (2016).

    Google Scholar 

  53. 53.

    Wang, Y. et al. van der Waals contacts between three-dimensional metals and two-dimensional semiconductors. Nature 568, 70–74 (2019).

    Google Scholar 

  54. 54.

    Kaasbjerg, K., Thygesen, K. S. & Jacobsen, K. W. Phonon-limited mobility in n-type single-layer MoS2 from first principles. Phys. Rev. B 85, 115317 (2012).

    Google Scholar 

  55. 55.

    Das, S., Chen, H. Y., Penumatcha, A. V. & Appenzeller, J. High performance multilayer MoS2 transistors with scandium contacts. Nano Lett. 13, 100–105 (2013).

    Google Scholar 

  56. 56.

    English, C. D., Shine, G., Dorgan, V. E., Saraswat, K. C. & Pop, E. Improved contacts to MoS2 transistors by ultra-high vacuum metal deposition. Nano Lett. 16, 3824–3830 (2016).

    Google Scholar 

  57. 57.

    Shen, T., Ren, J. C., Liu, X. Y., Li, S. & Liu, W. van der Waals stacking induced transition from Schottky to ohmic contacts: 2D metals on multilayer InSe. J. Am. Chem. Soc. 141, 3110–3115 (2019).

    Google Scholar 

  58. 58.

    Lee, D. H. et al. Ultrathin graphene intercalation in PEDOT:PSS/colorless polyimide-based transparent electrodes for enhancement of optoelectronic performance and operational stability of organic devices. ACS Appl. Mater. Interfaces 11, 21069–21077 (2019).

    Google Scholar 

  59. 59.

    Wang, Q. S. et al. Room-temperature nanoseconds spin relaxation in WTe2 and MoTe2 thin films. Adv. Sci. 5, 1700912 (2018).

    Google Scholar 

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Acknowledgements

This work was supported by the Nano-Material Technology Development Program (Grant no. 2017M3A7B8065377) through the National Research Foundation (NRF) of Korea funded by the Ministry of Science, ICT and Future Planning. This work has benefited from the use of the facilities at UNIST Central Research Facilities.

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S.S. performed most of the experiments with assistance from Y.S., S.-Y. Kim, D.H.L., J.W., S.Y., Y.L., J.K., J.-H.C.; J.H.K. and Z.L. performed the high-resolution TEM imaging of the samples; I.O. and J.-W.Y. performed the low-temperature magnetoresistance measurements; W.N. and H.C. performed the Raman measurements; S.S. and S.-Y. Kwon wrote the manuscript; all the authors revised and commented on the manuscript; S.-Y. Kwon planned and supervised the project.

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Correspondence to Soon-Yong Kwon.

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Supplementary Notes 1 and 2, Figs. 1–24 and Tables 1–3.

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Song, S., Sim, Y., Kim, SY. et al. Wafer-scale production of patterned transition metal ditelluride layers for two-dimensional metal–semiconductor contacts at the Schottky–Mott limit. Nat Electron 3, 207–215 (2020). https://doi.org/10.1038/s41928-020-0396-x

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