Nano Research

, Volume 9, Issue 8, pp 2319–2326 | Cite as

Toward negligible charge loss in charge injection memories based on vertically integrated 2D heterostructures

  • Dongri Qiu
  • Dong Uk Lee
  • Kyoung Su Lee
  • Sang Woo Pak
  • Eun Kyu KimEmail author
Research Article


Two-dimensional (2D) crystals have a multitude of forms, including semi-metals, semiconductors, and insulators, which are ideal for assembling isolated 2D atomic materials to create van der Waals (vdW) heterostructures. Recently, artificially-stacked materials have been considered promising candidates for nanoelectronic and optoelectronic applications. In this study, we report the vertical integration of layered structures for the fabrication of prototype non-volatile memory devices. A semiconducting-tungsten-disulfide-channel-based memory device is created by sandwiching high-density-of-states multi-layered graphene as a carrier-confining layer between tunnel barriers of hexagonal boron nitride (hBN) and silicon dioxide. The results reveal that a memory window of up to 20 V is opened, leading to a high current ratio (>103) between programming and erasing states. The proposed design combination produced layered materials that allow devices to attain perfect retention at 13% charge loss after 10 years, offering new possibilities for the integration of transparent, flexible electronic systems.


two-dimensional (2D) material graphene hexagonal boron nitride (hBN) tungsten disulphide (WS)2 heterostructure 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Supplementary material

12274_2016_1118_MOESM1_ESM.pdf (2.9 mb)
Supplementary material, approximately 2930 KB.


  1. [1]
    Wang, Q. H.; Kalantar-Zadeh, K.; Kis, A.; Coleman, J. N.; Strano, M. S. Electronics and optoelectronics of two-dimensional transition metal dichalcogenides. Nat. Nanotechnol. 2012, 7, 699–712.CrossRefGoogle Scholar
  2. [2]
    Ganatra, R.; Zhang, Q. Few-layer MoS2: A promising layered semiconductor. ACS Nano 2014, 8, 4074–4099.CrossRefGoogle Scholar
  3. [3]
    Roy, K.; Padmanabhan, M.; Goswami, S.; Sai, T. P.; Ramalingam, G.; Raghavan, S.; Ghosh, A. Graphene–MoS2 hybrid structures for multifunctional photoresponsive memory devices. Nat. Nanotechnol. 2013, 8, 826–830.CrossRefGoogle Scholar
  4. [4]
    Georgiou, T.; Jalil, R.; Belle, B. D.; Britnell, L.; Gorbachev, R. V.; Morozov, S. V.; Kim, Y. J.; Gholinia, A.; Haigh, S. J.; Makarovsky, O. et al. Vertical field-effect transistor based on graphene–WS2 heterostructures for flexible and transparent electronics. Nat. Nanotechnol. 2013, 8, 100–103.CrossRefGoogle Scholar
  5. [5]
    Mishchenko, A.; Tu, J. S.; Cao, Y.; Gorbachev, R. V.; Wallbank, J. R.; Greenaway, M. T.; Morozov, V. E.; Morozov, S. V.; Zhu, M. J.; Wong, S. L. et al. Twist-controlled resonant tunnelling in graphene/boron nitride/graphene heterostructures. Nat. Nanotechnol. 2014, 9, 808–813.CrossRefGoogle Scholar
  6. [6]
    Li, D.; Wang, X. J.; Zhang, Q. C.; Zou, L. P.; Xu, X. F.; Zhang, Z. X. Nonvolatile floating-gate memories based on stacked black phosphorus–boron nitride–MoS2 heterostructures. Adv. Funct. Mater. 2015, 25, 7360–7365.CrossRefGoogle Scholar
  7. [7]
    Choi, M. S.; Lee, G. H.; Yu, Y. J.; Lee, D. Y.; Lee, S. H.; Kim, P.; Hone, J.; Yoo, W. J. Controlled charge trapping by molybdenum disulphide and graphene in ultrathin heterostructured memory devices. Nat. Commun. 2013, 4, 1624.CrossRefGoogle Scholar
  8. [8]
    Wang, X. M.; Xie, W. G.; Xu, J. B. Graphene based nonvolatile memory devices. Adv. Mater. 2014, 26, 5496–5503.CrossRefGoogle Scholar
  9. [9]
    Bertolazzi, S.; Krasnozhon, D.; Kis, A. Nonvolatile memory cells based on MoS2/graphene heterostructures. ACS Nano 2013, 7, 3246–3252.CrossRefGoogle Scholar
  10. [10]
    Zhang, E. Z.; Wang, W. Y.; Zhang, C.; Jin, Y. B.; Zhu, G. D.; Sun, Q.-Q.; Zhang, D. W.; Zhou, P.; Xiu, F. X. Tunable charge-trap memory based on few-layer MoS2. ACS Nano 2015, 9, 612–619.CrossRefGoogle Scholar
  11. [11]
    Wang, J. L.; Zou, X. M.; Xiao, X. H.; Xu, L.; Wang, C. L.; Jiang, C. Z.; Ho, J. C.; Wang, T.; Li, J. C.; Liao, L. Floating gate memory-based monolayer MoS2 transistor with metal nanocrystals embedded in the gate dielectrics. Small 2015, 11, 208–213.CrossRefGoogle Scholar
  12. [12]
    Lee, J.; Min, S.-W.; Lee, H. S.; Yi, Y. J.; Im, S. MoS2 nanosheet channel and guanine DNA-base charge injection layer for high performance memory transistors. J. Mater. Chem. C 2014, 2, 5411–5416.CrossRefGoogle Scholar
  13. [13]
    Cao, W.; Kang, J. H.; Bertolazzi, S.; Kis, A.; Banerjee, K. Can 2D-nanocrystals extend the lifetime of floating-gate transistor based nonvolatile memory? IEEE T. Electron Dev. 2014, 61, 3456–3464.CrossRefGoogle Scholar
  14. [14]
    Hong, A. J.; Song, E. B.; Yu, H. S.; Allen, M. J.; Kim, J.; Fowler, J. D.; Wassei, J. K.; Park, Y.; Wang, Y.; Zou, J. et al. Graphene flash memory. ACS Nano 2011, 5, 7812–7817.CrossRefGoogle Scholar
  15. [15]
    Young, A. F.; Dean, C. R.; Meric, I.; Sorgenfrei, S.; Ren, H.; Watanabe, K.; Taniguchi, T.; Hone, J.; Shepard, K. L.; Kim, P. Electronic compressibility of layer-polarized bilayer graphene. Phys. Rev. B 2012, 85, 235458.CrossRefGoogle Scholar
  16. [16]
    Lee, G.-H.; Yu, Y.-J.; Lee, C.; Dean, C.; Shepard, K. L.; Kim, P.; Hone, J. Electron tunneling through atomically flat and ultrathin hexagonal boron nitride. Appl. Phys. Lett. 2011, 99, 243114.CrossRefGoogle Scholar
  17. [17]
    Osada, M.; Sasaki, T. Two-dimensional dielectric nanosheets: Novel nanoelectronics from nanocrystal building blocks. Adv. Mater. 2012, 24, 210–228.CrossRefGoogle Scholar
  18. [18]
    Dean, C. R.; Young, A. F.; Meric, I.; Lee, C.; Wang, L.; Sorgenfrei, S.; Watanabe, K.; Taniguchi, T.; Kim, P.; Shepard, K. L. et al. Boron nitride substrates for high-quality graphene electronics. Nat. Nanotechnol. 2010, 5, 722–726.CrossRefGoogle Scholar
  19. [19]
    Sik Hwang, W.; Remskar, M.; Yan, R. S.; Protasenko, V.; Tahy, K.; Doo Chae, S.; Zhao, P.; Konar, A.; Xing, H.; Seabaugh, A. et al. Transistors with chemically synthesized layered semiconductor WS2 exhibiting 105 room temperature modulation and ambipolar behavior. Appl. Phys. Lett. 2012, 101, 013107.CrossRefGoogle Scholar
  20. [20]
    Braga, D.; Gutiérrez Lezama, I.; Berger, H.; Morpurgo, A. F. Quantitative determination of the band gap of WS2 with ambipolar ionic liquid-gated transistors. Nano Lett. 2012, 12, 5218–5223.CrossRefGoogle Scholar
  21. [21]
    Kuc, A.; Zibouche, N.; Heine, T. Influence of quantum confinement on the electronic structure of the transition metal sulfide TS2. Phys. Rev. B 2011, 83, 245213.CrossRefGoogle Scholar
  22. [22]
    Huo, N. J.; Kang, J.; Wei, Z. M.; Li, S.-S.; Li, J. B.; Wei, S.-H. Novel and enhanced optoelectronic performances of multilayer MoS2–WS2 heterostructure transistors. Adv. Funct. Mater. 2014, 24, 7025–7031.CrossRefGoogle Scholar
  23. [23]
    Liu, L. T.; Bala Kumar, S.; Ouyang, Y. J.; Guo, J. Performance limits of monolayer transition metal dichalcogenide transistors. IEEE T. Electron Dev. 2011, 58, 3042–3047.CrossRefGoogle Scholar
  24. [24]
    Brainard, W. A. The Thermal Stability and Friction of the Disulfides, Diselenides, and Ditellurides of Molybdenum and Tungsten in Vacuum (10–9 to 10–6 Torr). NASA, Washington, 1969.Google Scholar
  25. [25]
    Ballif, C.; Regula, M.; Schmid, P. E.; Remškar, M.; Sanjinés, R.; Lévy, F. Preparation and characterization of highly oriented, photoconducting WS2 thin films. Appl. Phys. A 1996, 62, 543–546.Google Scholar
  26. [26]
    Zhu, W. J.; Perebeinos, V.; Freitag, M.; Avouris, P. Carrier scattering, mobilities, and electrostatic potential in monolayer, bilayer, and trilayer graphene. Phys. Rev. B 2009, 80, 235402.CrossRefGoogle Scholar
  27. [27]
    Kumar, J.; Kuroda, M. A.; Bellus, M. Z.; Han, S.-J.; Chiu, H.-Y. Full-range electrical characteristics of WS2 transistors. Appl. Phys. Lett. 2015, 106, 123508.CrossRefGoogle Scholar
  28. [28]
    Hwan Lee, S.; Lee, D.; Sik Hwang, W.; Hwang, E.; Jena, D.; Jong Yoo, W. High-performance photocurrent generation from two-dimensional WS2 field-effect transistors. Appl. Phys. Lett. 2014, 104, 193113.CrossRefGoogle Scholar
  29. [29]
    Qiu, D. R.; Kim, E. K. Electrically tunable and negative Schottky barriers in multi-layered graphene/MoS2 heterostructured transistors. Sci. Rep. 2015, 5, 13743.CrossRefGoogle Scholar
  30. [30]
    Late, D. J.; Liu, B.; Matte, H. S. S. R.; Dravid, V. P.; Rao, C. N. R. Hysteresis in single-layer MoS2 field effect transistors. ACS Nano 2012, 6, 5635–5641.CrossRefGoogle Scholar
  31. [31]
    Chen, M. K.; Nam, H.; Wi, S.; Priessnitz, G.; Gunawan, I. M.; Liang, X. G. Multibit data storage states formed in plasmatreated MoS2 transistors. ACS Nano 2014, 8, 4023–4032.CrossRefGoogle Scholar
  32. [32]
    Withers, F.; Bointon, T. H.; Hudson, D. C.; Craciun, M. F.; Russo, S. Electron transport of WS2 transistors in a hexagonal boron nitride dielectric environment. Sci. Rep. 2014, 4, 4967.CrossRefGoogle Scholar
  33. [33]
    Iqbal, M. W.; Iqbal, M. Z.; Khan, M. F.; Shehzad, M. A.; Seo, Y.; Park, J. H.; Hwang, C.; Eom, J. High-mobility and air-stable single-layer WS2 field-effect transistors sandwiched between chemical vapor deposition-grown hexagonal BN films. Sci. Rep. 2015, 5, 10699.CrossRefGoogle Scholar
  34. [34]
    Ovchinnikov, D.; Allain, A.; Huang, Y.-S.; Dumcenco, D.; Kis, A. Electrical transport properties of single-layer WS2. ACS Nano 2014, 8, 8174–8181.CrossRefGoogle Scholar
  35. [35]
    Brewer, J.; Gill, M. Nonvolatile Memory Technologies with Emphasis on Flash; Wiley-IEEE Press: Piscataway, NJ, 2008.Google Scholar
  36. [36]
    Yan, R. S.; Zhang, Q.; Li, W.; Calizo, I.; Shen, T.; Richter, C. A.; Hight-Walker, A. R.; Liang, X. L.; Seabaugh, A.; Jena, D. et al. Determination of graphene work function and graphene-insulator-semiconductor band alignment by internal photoemission spectroscopy. Appl. Phys. Lett. 2012, 101, 022105.CrossRefGoogle Scholar
  37. [37]
    Powers, M. J.; Benjamin, M. C.; Porter, L. M.; Nemanich, R. J.; Davis, R. F.; Cuomo, J. J.; Doll, G. L.; Harris, S. J. Observation of a negative electron affinity for boron nitride. Appl. Phys. Lett. 1995, 67, 3912–3914.CrossRefGoogle Scholar
  38. [38]
    Schroder, D. K. Semiconductor Material and Device Characterization, 3rd ed.; John Wiley & Sons: Hoboken, NJ, 2006.Google Scholar
  39. [39]
    Lenzlinger, M.; Snow, E. H. Fowler-nordheim tunneling into thermally grown SiO2. J. Appl. Phys. 1969, 40, 278–283.CrossRefGoogle Scholar
  40. [40]
    Han, S.-T.; Zhou, Y.; Roy, V. A. L. Towards the development of flexible non-volatile memories. Adv. Mater. 2013, 25, 5425–5449.CrossRefGoogle Scholar
  41. [41]
    Xu, Y.-N.; Ching, W. Y. Calculation of ground-state and optical properties of boron nitrides in the hexagonal, cubic, and wurtzite structures. Phys. Rev. B 1991, 44, 7787–7798.CrossRefGoogle Scholar
  42. [42]
    Jung, J.; Raoux, A.; Qiao, Z. H.; MacDonald, A. H. Ab initio theory of moiré superlattice bands in layered two-dimensional materials. Phys. Rev. B 2014, 89, 205414.CrossRefGoogle Scholar
  43. [43]
    Kharche, N.; Nayak, S. K. Quasiparticle band gap engineering of graphene and graphone on hexagonal boron nitride substrate. Nano Lett. 2011, 11, 5274–5278.CrossRefGoogle Scholar
  44. [44]
    Sze, S. M.; Ng, K. K. Physics of Semiconductor Devices, 3rd ed.; John Wiley & Sons: New Jersey, 2006.CrossRefGoogle Scholar
  45. [45]
    Qiu, D. R.; Lee, D. U.; Park, C. S.; Lee, K. S.; Kim, E. K. Transport properties of unrestricted carriers in bridge-channel MoS2 field-effect transistors. Nanoscale 2015, 7, 17556–17562.CrossRefGoogle Scholar

Copyright information

© Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Dongri Qiu
    • 1
  • Dong Uk Lee
    • 2
  • Kyoung Su Lee
    • 1
  • Sang Woo Pak
    • 1
  • Eun Kyu Kim
    • 1
    Email author
  1. 1.Quantum-Function Research Laboratory and Department of PhysicsHanyang UniversitySeoulRepublic of Korea
  2. 2.NAND Development DivisionNAND Product Engineering Group, SK HynixIcheonRepublic of Korea

Personalised recommendations