Device Applications of Metal-2D-Materials Interfaces A Short Review



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Submitted Nov 20, 2017
Published Apr 3, 2018
10.24018/ejeng.2018.3.4.524

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The electronic energy band gaps of 2D-materials are known to spread over a wide range from zero in graphene to > 6eV in hexagonal boron nitride (h-BN). Various combinations of such engineered nanomaterials offer a number of novel device applications involving their unique optical, electronic, and thermal properties along with their higher charge carrier mobilities and saturation limited drift velocities. Structurally, these nanomaterials have single or multiple monolayers stuck together, which are not only suitable for flexible electron devices and circuits but also in preparing heterostructures (lateral as well as vertical configurations) that form super lattices with different kinds of band alignments. Such possibilities offer flexible control over the charge carrier transport in these materials via numerous types of exciton formations. Their extra sensitivity towards the presence of atomic, molecular and nanoparticulate species in their vicinity is the most significant aspect of these 2D-materials. This is the reason behind studying them in detail for detecting the presence of extremely low concentrations of the analyte that are not achievable in conventional sensors. For translating the above-said superlative properties of these fast emerging families of 2-D nanomaterials into usable devices and circuits, applying the conventional device fabrication technologies poses a real challenge. The experimental results reported in the context of forming usable interfaces between a metal and 2D-nanomaterial are examined here to assess their current status and future prospects. Their widespread applications are certainly anticipated in the fields like printed micro/nano sensors, large area electronics and printed intelligence with special reference to their emerging usages in Internet of Things (IoT) in the near future. 

Keywords: 2D-Semiconductors 2D-FET Structures Edge Contacts Fermi Level Pinning Metal-Semiconductor Contacts Planar Contacts Schottky Barrier Heights

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References

  1. S. Ahmad, Micro and Millimeter Wave Semiconductor Device Technology. Tata McGraw Hill, Delhi, India, 1998.
     Google Scholar
  2. A. Allain, J. Kang, K. Banerjee, and A. Kis, “Electrical contacts to two-dimensional semiconductors,” Nature Materials, vol. 14, pp. 1195-1205, 2015.
     Google Scholar
  3. O. Lopez-Sanchez, D. Lembke, M. Kayci, A. Radenovic, and A. Kis, “Ultrasensitive photo detectors based on monolayer MoS2,” Nature Nanotech., vol. 8, pp. 497–501, 2013.
     Google Scholar
  4. D. Krasnozhon, D. Lembke, C. Nyffeler, Y. Leblebici, and A. Kis, “MoS2 transistors operating at gigahertz frequencies,” Nano Lett., vol. 14, pp. 5905-11, 2014.
     Google Scholar
  5. S. Das, H. Y. Chen, A. V. Penumatcha, and J. Appenzeller, (2013), “High performance multilayer MoS2 transistors with scandium contacts,” Nano Lett., vol. 13, pp. 100–105, 2013.
     Google Scholar
  6. H. Liu, A. T. Neal, and P. D. Ye, “Channel length scaling of MoS2 MOSFETs,” ACS Nano., vol. 6, pp. 8563-9, 2012.
     Google Scholar
  7. H. Liu, M. Si, S. Najmaei, A. T. Neal, Y. Du, P. M. Ajayan, J. Lou, and P. D. Ye, “Statistical study of deep submicron dual-gated field-effect transistors on monolayer chemical vapor deposition molybdenum disulfide films,” Nano Lett., vol. 13, pp. 2640–6, 2013.
     Google Scholar
  8. R. Landauer, “Spatial variation of currents and fields due to localized scatterers in metallic conduction,” IBM J. Res. Dev. vol.1, pp. 223–231, 1957.
     Google Scholar
  9. Y. V. Sharvin, “A possible method for studying Fermi surfaces,” Sov. Phys. JETP, vol. 21, pp. 655-6, 1965.
     Google Scholar
  10. D. Jena, K. Banerjee, and G. H. Xing, “2D crystal semiconductors: Intimate contacts,” Nature Mater., vol. 13, pp. 1076-8, 2014.
     Google Scholar
  11. G. T. Wright, “Small-signal theory of the transistor transit-time oscillator /translator/,” Solid-State Electronics, vol. 22(4), pp. 399-403, 1979.
     Google Scholar
  12. S. M. Sze, Physics of Semiconductor Devices, Wiley-Inter science, 1969.
     Google Scholar
  13. J. Bardeen, “Surface States and Rectification at a Metal Semi-Conductor Contact,” Phys. Rev. vol. 71, 717, 1947.
     Google Scholar
  14. Y. Xu, C. Cheng, S. Du, J. Yang, Bin Yu, J. Luo, W. Yin, E. Li, S. Dong, P. Ye, and X. Duan, “Contacts between Two and Three-Dimensional Materials: Ohmic, Schottky, and p-n Hetero junctions,” ACS Nano, vol. 10 (5), pp. 4895-919, 2016.
     Google Scholar
  15. S. Das, H.-Y. Chen, A. V. Penumatcha, and J. Appenzeller, “High-Performance Multilayer MoS2 Transistors with Scandium Contacts,” Nano Lett., 13 (1), pp. 100–105, 2013.
     Google Scholar
  16. Y. Zhao, X. Xiao, Y. Huo, Y. Wang, T. Zhang, K. Jiang, J. Wang, S. Fan, and Q. Li, “Influence of Asymmetric Contact Form on Contact Resistance and Schottky Barrier, and Corresponding Applications of Diode,” ACS Appl. Mater. Interfaces, vol. 9 (22), pp.18945-55, 2017.
     Google Scholar
  17. K. S. Kim, K. H. Kim, Y. Nam, J. Jeon, S. Yim, E. Singh, J. Y. Lee, S. J. Lee, Y. S. Jung, G. Y. Yeom, and D. W. Kim, “Atomic layer etching mechanism of MoS2 for nano devices,” ACS Appl. Mater. Interfaces, vol. 9 (13), pp. 11967-76, 2017.
     Google Scholar
  18. S. Roy, G. P. Neupane, K. P. Dhakal, J. Lee, S. J. Yun, G. H. Han, and J. Kim, “Observation of Charge transfer in heterostructures composed of MoSe2 quantum dots and a monolayer of MoS2 or WSe2,” J. Phys. Chem. C, vol. 121 (3), pp. 1997–2004, 2017.
     Google Scholar
  19. M.-H. Doan, Y. Jin, S. Adhikari, S. Lee, J. Zhao, S. C. Lim, and Y. H. Lee, “Charge transport in MoS2/WSe2 van der Waals hetero-structure with tunable inversion layer,” ACS Nano, vol. 11 (4), pp. 3832-40, 2017.
     Google Scholar
  20. J. S. Ross, P. Rivera, J. Schaibley, E. Lee-Wong, H. Yu, T. Taniguchi, K. Watanabe, J. Yan, D. Mandrus, D. Cobden, W. Yao, and X. Xu, (2017), Interlayer exciton optoelectronics in a 2D hetero structure p–n Junction,” Nano Lett., vol. 17 (2), pp. 638-43, 2017.
     Google Scholar
  21. K. Xu, D. Chen, F. Yang, Z. Wang, L. Yin, F. Wang, R. Cheng, K. Liu, J. Xiong, Q. Liu, and J. He, “Sub-10nm nano pattern architecture for 2D material field-effect transistors,” Nano Lett., vol. 17 (2), pp. 1065–70, 2017.
     Google Scholar
  22. C. Kim, I. Moon, D. Lee, M. S. Choi, F. Ahmed, S. Nam, Y. Cho, H.-J. Shin, S. Park, and W. J. Yoo, “Fermi level pinning at electrical metal contacts of monolayer Molybdenum Dichalcogenides,” ACS Nano, vol.11 (2), pp.1588-96, 2017.
     Google Scholar
  23. J. Guan, H.-J. Chuang, Z. Zhou, and D. Tománek, “Optimizing charge injection across transition metal di-chalcogenide heterojunctions: Theory and Experiment,” ACS Nano, vol. 11 (4), pp. 3904-10, 2017.
     Google Scholar
  24. C. Zheng, Q. Zhang, B. Weber, H. Ilatikhameneh, F. Chen, H. Sahasrabudhe, R. Rahman, S. Li, Z. Chen, J. Hellerstedt, Y. Zhang, W. H. Duan, Q. Bao, and M. S. Fuhrer, “Direct observation of 2D electrostatics and ohmic contacts in template-grown graphene/WS2 heterostructures,” ACS Nano, vol. 11 (3), pp. 2785–93, 2017.
     Google Scholar
  25. D. Stradi, N. R. Papior, O. Hansen, and M. Brandbyge, “Field Effect in graphene-based van der Waals heterostructures: Stacking sequence matters,” Nano Lett., vol. 17 (4), pp. 2660–6, 2017.
     Google Scholar
  26. R. Li, L. Zhang, L. Shi, and P. Wang, “MXene Ti3C2: An effective 2D light-to-heat conversion material,” ACS Nano, vol. 11 (4), pp. 3752–9, 2017.
     Google Scholar
  27. H. Lin, X. Wang, L. Yu, Y. Chen, and J. Shi, “Two-dimensional ultrathin MXene ceramic nanosheets for photo-thermal conversion,” Nano Lett., vol. 17 (1), pp. 384-91, 2017.
     Google Scholar
  28. L. Huang, B. Li, M. Zhong, Z. Wei, and J. Li, “Tunable Schottky barrier at MoSe2/Metal interfaces with a buffer layer,” J. Phys. Chem. C, vol. 121 (17), pp. 9305–11, 2017.
     Google Scholar
  29. Y. Yoon, K. Ganapathi, and S. Salahuddin, “How good can monolayer MoS2 transistors be?” Nano Lett., vol. 11 (9), pp. 3768–73, 2011.
     Google Scholar
  30. H. Wang, L. Yu, Y.-H. Lee, Y. Shi, A. Hsu, M. L. Chin, L.-J. Li, M. Dubey, J. Kong, and T. Palacios, “Integrated circuits based on bilayer MoS2 transistors,” Nano Lett., vol. 12 (9), pp. 4674–80, 2012.
     Google Scholar
  31. S. Sattar and U. Schwingenschlögl, “Electronic properties of graphene–PtSe2 contacts,” ACS Appl. Mater. Interfaces, vol. 9 (18), pp.15809-13, 2017.
     Google Scholar
  32. H. G. Kim, and H.-B.-R. Lee, “Atomic layer deposition on 2D materials,” Chem. Mater., vol. 29(9), pp. 3809-26, 2017.
     Google Scholar
  33. A. Nourbakhsh, A. Zubair, R. N. Sajjad, A. Tavakkoli K. G. W. Chen, S. Fang, X. Ling, J. Kong, M. S. Dresselhaus, E. Kaxiras, K. K. Berggren, D. Antoniadis, and T. Palacios, “MoS2 field-effect transistor with sub-10nm channel length,” Nano Lett. vol. 16 (12), pp. 7798–7806, 2016.
     Google Scholar
  34. W. S. Leong, X. Luo, Y. Li, K. H. Khoo, S. Y. Quek, and J. T. L. Thong, “Low resistance metal contacts to MoS2 devices with nickel-etched-graphene electrodes,” ACS Nano, vol. 9 (1), pp. 869-77, 2015.
     Google Scholar
  35. H.-J. Chuang, B. Chamlagain, M. Koehler, M. M. Perera, J. Yan, D. Mandrus, D. Tománek, and Z. Zhou, “Low-resistance 2D/2D ohmic contacts: A universal approach to high-performance WSe2, MoS2, and MoSe2 transistors,” Nano Lett., vol. 16 (3), pp. 1896–1902, 2016.
     Google Scholar
  36. Y. Kim, A. R. Kim, J. H. Yang, K. E. Chang, J.-D. Kwon, S. Y. Choi, J. Park, K. E. Lee, D.-H. Kim, S. M. Choi, K. H. Lee, B. H. Lee, M. G. Hahm, and B. Cho, “Alloyed 2D metal–semiconductor heterojunctions: Origin of interface states reduction and Schottky barrier Lowering,” Nano Lett., vol. 16 (9), pp. 5928–33, 2016.
     Google Scholar
  37. Y. Sata, R. Moriya, S. Masubuchi, K. Watanabe, T. Taniguchi, and T. Machida, “N and P-type carrier injections into WSe2 with van der Waals contacts of two-dimensional materials,” Jap. J. App. Phys., vol. 56, 04CK09, 2017.
     Google Scholar
  38. D. Kufer, and G. Konstantatos, “Photo-FETs: Phototransistors enabled by 2D and 0D Nanomaterials,” ACS Photonics, vol. 3 (12), pp. 2197–2210, 2016.
     Google Scholar
  39. H. Zhong, R. Quhe, Y. Wang, Z. Ni, M. Ye, Z. Song, Y. Pan, J. Yang, L. Yang, M. Lei, J. Shi, and J. Lu, “Interfacial properties of monolayer and bilayer MoS2 contacts with metals: Beyond the energy band calculations,” Scientific Rep. 6:21786, 2016. DOI: 10.1038/ srep21786
     Google Scholar
  40. C. P. Y. Wong, C. Troadec, K. E. J. Goh, and A. T. S. Wee, “A study of the metal/2D semiconductor contacts,” 2017. Text @ www.physics.nus.edu.sg/~surface/Posters /Calvin % 20Wong_Poster%20-%20ISRF%20 2015. pdf
     Google Scholar
  41. A. Bin Khudhayr, 2017, Text @ http://userweb.eng.gla.ac.uk/MScPosters2014-15/ Engineering%20and%20Management/EEE%20 and%20Management/Developing%20of%20Lowresistance%20Ohmic%20Contact%20on%20GaN % 20 HEMTs.pdf
     Google Scholar
  42. D. Taneja, F. Sfigakis, A. F. Croxall, K. Das Gupta, V. Narayan, J. Waldie, I. Farrer, and D. A. Ritchie, “N-type ohmic contacts to undoped GaAs/AlGaAs quantum wells using only front-sided processing: application to ambipolar FETs,” Semicond. Sci. Technol., vol. 31, 065013 (7pp), 2016.
     Google Scholar
  43. P. Parikh, Y. Wu, and L. Shen, “Commercialization of high 600V GaN-on-silicon power HEMTs and diodes. IEEE Energytech., pp. 21-23, May 2013; DOI: 10.1109/EnergyTech. 2013.6645300
     Google Scholar
  44. L. Wang, I. Meric, P. Y. Huang, Q. Gao, Y. Gao, H. Tran, T. Taniguchi, K. Watanabe, L. M. Campos, D. A. Muller, J. Guo, P. Kim, J. Hone, K. L. Shepard, and C. R. Dean, “One-dimensional electrical contact to a two-dimensional material,” Science, vol. 342, pp. 614-7, 2013.
     Google Scholar
  45. G. Giovannetti, P. A. Khomyakov, G. Brocks, V. M. Karpan, J. van den Brink, and P. J. Kelly, “Doping graphene with metal contacts,” Phys. Rev. Lett., vol. 101, 026803, 2008.
     Google Scholar
  46. Q. Tang, C. X. Zhang, C. He, C. Tang, and J. Zhong, “Charge transport properties of graphene: Effects of Cu-based gate electrode,” J. Appl. Phys., vol.108, 123711, 2010.
     Google Scholar
  47. F. Léonard, and A. A. Talin, “Electrical contacts to one- and two-dimensional nanomaterials,” Nat. Nanotechnol., vol. 6, pp.773-83, 2011.
     Google Scholar
  48. F. Xia, V. Perebeinos, Y. M. Lin, Y. Wu, and P. Avouris, “The origins and limits of metal-graphene junction resistance. Nat. Nanotechnol. 6, 179-84, 2011.
     Google Scholar
  49. M. S. Choi, S. H. Lee, and W. J. Yoo, “Plasma treatments to improve metal contacts in graphene field effect transistor,” J. Appl. Phys., vol. 110, 073305, 2011.
     Google Scholar
  50. D. Berdebes, T. Low, Y. Sui, J. Appenzeller, and M. S. Lundstrom, “Substrate gating of contact resistance in graphene transistors,” IEEE Trans. Electron. Dev., vol. 58, pp. 3925-32, 2011.
     Google Scholar
  51. J. S. Moon, M. Antcliffe, H. C. Seo, D. Curtis, S. Lin, A. Schmitz, I. Milosavljevic, A. A. Kiselev, R. S. Ross, D. K. Gaskill, P. M. Campbell, R. C. Fitch, K.-M. Lee, and P. Asbeck, “Ultra-low resistance ohmic contacts in graphene field effect transistors,” Appl. Phys. Lett. vol.100, 203512, 2012.
     Google Scholar
  52. J. T. Smith, A. D. Franklin, D. B. Farmer, and C. D. Dimitrakopoulos, “Reducing contact resistance in graphene devices through contact area patterning,” ACS Nano vol. 7, pp. 3661–7, 2013.
     Google Scholar
  53. A. K. Geim, and I. V. Grigorieva, “van der Waals heterostructures,” Nature vol. 499, pp. 419-25, 2013.
     Google Scholar
  54. A. S. Mayorov, R. V. Gorbachev, S. V. Morozov, L. Britnell, R. Jalil, L. A. Ponomarenko, P. Blake, K. S. Novoselov, K. Watanabe, T. Taniguchi, and A. K. Geim, “Micrometer-scale ballistic transport in encapsulated graphene at room temperature,” Nano Lett., vol. 11, pp. 2396–9, 2011.
     Google Scholar
  55. M. Ishigami, J. H. Chen, W. G. Cullen, M. S. Fuhrer, and E. D. Williams, “Atomic structure of graphene on SiO2,” Nano Lett., vol.7, pp. 1643–1648, 2007.
     Google Scholar
  56. J. A. Robinson, M. LaBella, M. Zhu, M. Hollander, R. Kasarda, Z. Hughes, K. Trumbull, R. Cavalero, and D. Snyder, “Contacting graphene,” Appl. Phys. Lett., vol. 98, 053103, 2011.
     Google Scholar
  57. J. Yamaguchi, K. Hayashi, S. Sato, and N. Yokoyama, “Passivating chemical vapor deposited graphene with metal oxides for transfer and transistor fabrication processes,” Appl. Phys. Lett., vol. 102, 143505, 2013.
     Google Scholar
  58. N. Lindvall, A. Kalabukhov, and A. Yurgens, “Erratum: “Cleaning graphene using atomic force microscope,” [J. Appl. Phys., vol. 111, 064904, 2012], J. Appl. Phys. vol. 111, 064904, 2012.
     Google Scholar
  59. S. J. Haigh, A. Gholinia, R. Jalil, S. Romani, L. Britnell, D. C. Elias, K. S. Novoselov, L. A. Ponomarenko, A. K. Geim, and R. Gorbachev, “Cross-sectional imaging of individual layers and buried interfaces of graphene-based heterostructures and superlattices,” Nat. Mater., vol. 11, pp. 764-7, 2012.
     Google Scholar
  60. Y. Matsuda, W.-Q. Deng, And W. A. Goddard Iii, “Contact Resistance for “End-Contacted” Metal-Graphene and Metal-Nanotube Interfaces from Quantum Mechanics,” J. Phys. Chem. C, Vol. 114, Pp. 17845–50, 2010.
     Google Scholar
  61. K. Cho, “First-Principles and Quantum Transport Studies of Metal–Graphene End Contacts,” Mrs Proc., Vol., 1259, Pp. S14–S35, 2010.
     Google Scholar
  62. Y. Wu, Y. Wang, J. Wang, M. Zhou, A. Zhang, C. Zhang, Y. Yang, Y. Hua, and B. Xu, “Electrical transport across metal-two-dimensional carbon junctions: edge versus side contacts,” AIP Adv., vol. 2(1), 012132, 2012.
     Google Scholar
  63. M. H. D. Guimarães, H. Gao, Y. Han, K. Kang, S. Xie, C.-J. Kim, D. A. Muller, D. C. Ralph, J. Park, “Atomically Thin Ohmic Edge Contacts Between Two-Dimensional Materials,” Acs Nano., Vol. 10 (6), Pp. 6392–9, 2016.
     Google Scholar
  64. Y. Wen, L. Yin, P. He, Z. Wang, X. K. Zhang, Q. Wang, T. A. Shifa, K. Xu, F. Wang, X. Zhan, F. Wang, C. Jiang, And J. He, “Integrated High-Performance Infrared Phototransistor Arrays Composed of Non-Layered Pbs–Mos2 Heterostructures with Edge Contacts,” Nano Lett., Vol. 16 (10), Pp. 6437–6444, 2016.
     Google Scholar
  65. T. Chu and Z. Chen, “Understanding The Electrical Impact of Edge Contacts in Few-Layer Graphene,” Acs Nano, Vol. 8 (4), Pp. 3584-9, 2014.
     Google Scholar
  66. W. S. Leong, X. Luo, Y. Li, K. H. Khoo, S. Y. Quek, And J. T. L. Thong, “Low-Resistance Metal Contacts to Mos2 Devices with Nickel-Etched-Graphene Electrodes,” Acs Nano, Vol. 9 (1), Pp. 869–877, 2015.
     Google Scholar
  67. C. D. English, G. Shine, V. E. Dorgan, K. C. Saraswat, And E. Pop, “Improved Contacts to Mos2 Transistors by Ultra-High Vacuum Metal Deposition,” Nano Lett., Vol. 16 (6), Pp. 3824-30, 2016.
     Google Scholar
  68. H. -J. Chuang, B. Chamlagain, M. Koehler, M. M. Perera, J. Yan, D. Mandrus, D. Tománek, and Z. Zhou, “Low-resistance 2D/2D ohmic contacts: A universal approach to high-performance WSe2, MoS2, and MoSe2 transistors,” Nano Lett., vol. 16 (3), pp. 1896–1902, 2016.
     Google Scholar
  69. X. Cui, E.-M. Shih, L. A. Jauregui, S. H. Chae, Y. D. Kim, B. Li, D. Seo, K. Pistunova, J. Yin, J.-H. Park, H.-J. Choi, Y. H. Lee, K. Watanabe, T. Taniguchi, P. Kim, C. R. Dean, and J. C. Hone, “Low-temperature ohmic contact to monolayer MoS2 by van der Waals bonded Co/h-BN electrodes,” Nano Lett., vol. 17 (8), pp. 4781–6, 2017.
     Google Scholar
  70. A. Avsar, J. Y. Tan, X. Luo, K. H. Khoo, Y. Yeo, K. Watanabe, T. Taniguchi, S. Y. Quek, and B. Özyilmaz, “van der Waals bonded Co/h-BN contacts to ultrathin black phosphorus devices,” Nano Lett., vol. 17 (9), pp. 5361–7, 2017.
     Google Scholar
  71. H.-J. Kwon, W. Choi, D. Lee, Y. Lee, J. Kwon, B. Yoo, C. P. Grigoropoulos, and S. Kim, “Selective and localized laser-anneal effect for high-performance flexible multilayer MoS2 thin-film transistors,” Nano Res., vol. 7, 1137, 2014.
     Google Scholar
  72. Y. Liu, H. Xiao, and W. A. Goddard, “Schottky-barrier-free contacts with two-dimensional semiconductors by surface-engineered MXenes,” J. Am. Chem. Soc., vol. 138 (49), pp. 15853-6, 2016.
     Google Scholar
  73. T. Hu, Z. Li, M. Hu, J. Wang, Q. Hu, Q. Li, and X. Wang, “Chemical origin of termination-functionalized MXenes: Ti3C2T2 as a case study,” J. Phys. Chem. C, vol. 121 (35), pp. 19254-61, 2017.
     Google Scholar
  74. Y. Wang, M. Ye, M. Weng, J. Li, X. Zhang, H. Zhang, Y. Guo, Y. Pan, L. Xiao, J. Liu, F. Pan, and J. Lu, “Electrical contacts in monolayer arsenene devices,” ACS Appl. Mater. Interfaces, vol. 9 (34), pp. 29273–84, 2017.
     Google Scholar
  75. Y. Guo, W. A. Saidi, and Q. Wang, “2D halide perovskite-based van der Waals heterostructures: contact evaluation and performance modulation,” 2D Materials, vol. 4(3), 035009, 2017.
     Google Scholar
  76. Y. Ma, A. Kuc, Y. Jing, P. Philipsen, and T. Heine, “Two-dimensional haeckelite NbS2: A diamagnetic high-mobility semiconductor with Nb4+ ions,” Angew. Chem. Int. Ed., vol. 56, 10214, 2017.
     Google Scholar
  77. X. Zhang, Y. Pan, M. Ye, R. Quhe, Y. Wang, Y. Guo, H. Zhang, Y. Dan, Z. Song, J. Li, J. Yang, W. Guo, and J. Lu, “Three-layer phosphorene-metal interfaces,” Nano Res., 2017; https://doi.org/10. 1007/s12274-017-1680-6
     Google Scholar
  78. H. A. Tahini, X. Tan, and S. C. Smith, “The origin of low work functions in OH-terminated MXenes,” Nanoscale, vol. 9, pp. 7016-20, 2017.
     Google Scholar
  79. E. Balc, U. O. Akkuş, and S. Berber, “Band gap modification in doped MXene: Sc2CF2,” J. Mater. Chem. C, vol. 5, pp. 5956-61, 2017.
     Google Scholar
  80. J. H. Sung, H. Heo, S. Si, Y. H. Kim, H. R. Noh, K. Song, J. Kim, C.-S. Lee, S.-Y. Seo, D.-H. Kim, H. K. Kim, H. W. Yeom, T.-H. Kim, S.-Y. Choi, J. S. Kim, and M.-H. Jo, “Coplanar semiconductor–metal circuitry defined on few-layer MoTe2 via polymorphic heteroepitaxy,” Nature Nanotechnology, 2017; doi:10.1038/nnano.2017.161
     Google Scholar
  81. Y. Matsuda, W.-Q. Deng, and W. A. Goddard III, “Contact resistance for “end-contacted” metal−graphene and metal−nanotube interfaces from quantum mechanics,” J. Phys. Chem. C, vol. 114 (41), 17845–50, 2010.
     Google Scholar
  82. K. H. Khoo, W. S. Leong, J. T. L. Thong, and S. Y. Quek, “Origin of contact resistance at ferromagnetic metal–graphene interfaces,” ACS Nano, vol. 10 (12), pp. 11219–27, 2016.
     Google Scholar
  83. M. Shaygan, M. Otto, A. A. Sagade, C. A. Chavarin, G. Bacher, W. Mertin, and D. Neumaier, “Low resistive edge contacts to CVD-grown graphene using a CMOS compatible metal,” Annalen der Physik, 1600410, 2017.
     Google Scholar
  84. Y. Xu, C. Cheng, S. Du, J. Yang, B. Yu, J. Luo, W. Yin, E. Li, S. Dong, P. Ye, and X. Duan, “Contacts between two and three-dimensional materials: Ohmic, Schottky, and p–n - heterojunctions,” ACS Nano, vol. 10 (5), pp. 4895-919, 2016.
     Google Scholar
  85. Y. Kim, A. R. Kim, J. H. Yang, K. E. Chang, J.-D. Kwon, S. Y. Choi, J. Park, K. E. Lee, D.-H. Kim, S. M. Choi, K. H. Lee, B. H. Lee, M. G. Hahm, and B. Cho, “Alloyed 2D-metal–semiconductor heterojunctions: Origin of interface states reduction and Schottky barrier lowering,” Nano Lett., vol. 16 (9), pp. 5928–33, 2016.
     Google Scholar
  86. 2-D Electronics' metal or semiconductor? Both, Researchers produced the first 2D field-effect transistor (FET) made of a single material, Science News, September, 2017, Text @ https://www.sciencedaily.com/releases /2017/09/ 170918161531. Htm
     Google Scholar
  87. J. H. Sung, H. Heo, S. Si, Y. H. Kim, H. R. Noh, K. Song, J. Kim, C.-S. Lee, S.-Y. Seo, D.-H. Kim, H. K. Kim, H. W. Yeom, T.-H. Kim, S.-Y. Choi, J. S. Kim, and M.-H. Jo, “Coplanar semiconductor–metal circuitry defined on few-layer MoTe2 via polymorphic heteroepitaxy,” Nature Nanotechnology, 2017; DOI: 10.1038/NNANO.2017.161.
     Google Scholar