Graphical Abstract

Semiconducting monolayer (ML) blue phosphorene (BlueP) shares similar stability with ML black phosphorene (BP), and it has recently been grown on an Au surface. Potential ML BlueP devices often require direct contact with metal to enable the injection of carriers. Using ab initio electronic structure calculations and quantum transport simulations, for the first time, we perform a systematic study of the interfacial properties of ML BlueP in contact with metals spanning a wide work function range in a field effect transistor (FET) configuration. ML BlueP has undergone metallization owing to strong interaction with five metals. There is a strong Fermi level pinning (FLP) in the ML BlueP FETs due to the metal-induced gap states (MIGS) with a pinning factor of 0.42. ML BlueP forms n-type Schottky contact with Sc, Ag, and Pt electrodes with electron Schottky barrier heights (SBHs) of 0.22, 0.22, and 0.80 eV, respectively, and p-type Schottky contact with Au and Pd electrodes with hole SBHs of 0.61 and 0.79 eV, respectively. The MIGS are eliminated by inserting graphene between ML BlueP and the metal electrode, accompanied by a transition from a strong FLP to a weak FLP. Our study not only provides insight into the ML BlueP–metal interfaces, but also helps in the design of ML BlueP devices.
Fiori, G.; Bonaccorso, F.; Iannaccone, G.; Palacios, T.; Neumaier, D.; Seabaugh, A.; Banerjee, S. K.; Colombo, L. Electronics based on two-dimensional materials. Nat. Nanotechnol. 2014, 9, 768–779.
Kang, J. H.; Liu, W.; Sarkar, D.; Jena, D.; Banerjee, K. Computational study of metal contacts to monolayer transition-metal dichalcogenide semiconductors. Phy. Rev. X 2014, 4, 031005.
Schwierz, F.; Pezoldt, J.; Granzner, R. Two-dimensional materials and their prospects in transistor electronics. Nanoscale 2015, 7, 8261–8283.
Das, S.; Zhang, W.; Demarteau, M.; Hoffmann, A.; Dubey, M.; Roelofs, A. Tunable transport gap in phosphorene. Nano Lett. 2014, 14, 5733–5739.
Guan, J.; Zhu, Z.; Tománek, D. Phase coexistence and metalinsulator transition in few-layer phosphorene: A computational study. Phys. Rev. Lett. 2014, 113, 046804.
Xiao, J.; Long, M. Q.; Zhang, X. J.; Ouyang, J.; Xu, H.; Gao, Y. L. Theoretical predictions on the electronic structure and charge carrier mobility in 2D phosphorus sheets. Sci. Rep. 2015, 5, 9961.
Liu, H.; Neal, A. T.; Zhu, Z.; Luo, Z.; Xu, X. F.; Tománek, D.; Ye, P. D. Phosphorene: An unexplored 2D semiconductor with a high hole mobility. ACS Nano 2014, 8, 4033–4041.
Li, L. K.; Yu, Y. J.; Ye, G. J.; Ge, Q. Q.; Ou, X. D.; Wu, H.; Feng, D. L.; Chen, X. H.; Zhang, Y. B. Black phosphorus field-effect transistors. Nat. Nanotechnol. 2014, 9, 372–377.
Buscema, M.; Groenendijk, D. J.; Blanter, S. I.; Steele, G. A.; van der Zant, H. S. J.; Castellanos-Gomez, A. Fast and broadband photoresponse of few-layer black phosphorus field-effect transistors. Nano Lett. 2014, 14, 3347–3352.
Zhu, Z.; Tománek, D. Semiconducting layered blue phosphorus: A computational study. Phys. Rev. Lett. 2014, 112, 176802.
Zhang, J. L.; Zhao, S. T.; Han, C.; Wang, Z. Z.; Zhong, S.; Sun, S.; Guo, R.; Zhou, X.; Gu, C. D.; Yuan, K. D. et al. Epitaxial growth of single layer blue phosphorus: A new phase of two-dimensional phosphorus. Nano Lett. 2016, 16, 4903–4908.
Allain, A.; Kang, J. H.; Banerjee, K.; Kis, A. Electrical contacts to two-dimensional semiconductors. Nat. Mater. 2015, 14, 1195–1205.
Liu, Y. Y.; Stradins, P.; Wei, S. H. Van der Waals metalsemiconductor junction: Weak Fermi level pinning enables effective tuning of Schottky barrier. Sci. Adv. 2016, 2, e1600069.
Quhe, R.; Peng, X. Y.; Pan, Y. Y.; Ye, M.; Wang, Y. Y.; Zhang, H.; Feng, S. Y.; Zhang, Q. X.; Shi, J. J.; Yang, J. B. et al. Can a black phosphorus Schottky barrier transistor be good enough? ACS Appl. Mater. Interfaces 2017, 9, 3959–3966.
Wang, J. L.; Yao, Q.; Huang, C. W.; Zou, X. M.; Liao, L.; Chen, S. S.; Fan, Z. Y.; Zhang, K.; Wu, W.; Xiao, X. H. et al. High mobility MoS2 transistor with low Schottky barrier contact by using atomic thick h-BN as a tunneling layer. Adv. Mater. 2016, 28, 8302–8308.
Farmanbar, M.; Brocks, G. Controlling the Schottky barrier at MoS2/metal contacts by inserting a B Nmonolayer. Phys. Rev. B 2015, 91, 161304.
Chuang, H. J.; Chamlagain, B.; Koehler, M.; Perera, M. M.; Yan, J. Q.; Mandrus, D.; Tománek, D.; Zhou, Z. X. Lowresistance 2D/2D ohmic contacts: A universal approach to high-performance WSe2, MoS2, and MoSe2 transistors. Nano Lett. 2016, 16, 1896–1902.
Kim, A. R.; Kim, Y.; Nam, J.; Chung, H. S.; Kim, D. J.; Kwon, J. D.; Park, S. W.; Park, J.; Choi, S. Y.; Lee, B. H. et al. Alloyed 2D metal-semiconductor atomic layer junctions. Nano Lett. 2016, 16, 1890–1895.
Liu, Y. Y.; Xiao, H.; Goddard III, W. A. Schottky-barrierfree contacts with two-dimensional semiconductors by surfaceengineered MXenes. J. Am. Chem. Soc. 2016, 138, 15853–15856.
Cho, S.; Kim, S.; Kim, J. H.; Zhao, J.; Seok, J.; Keum, D. H.; Baik, J.; Choe, D. H, ; Chang, K. J.; Suenaga, K. et al. Phase patterning for ohmic homojunction contact in MoTe2. Science 2015, 349, 625–628.
Kappera, R.; Voiry, D.; Yalcin, S. E.; Branch, B.; Gupta, G.; Mohite, A. D.; Chhowalla, M. Phase-engineered low-resistance contacts for ultrathin MoS2 transistors. Nat. Mater. 2014, 13, 1128–1134.
Liu, Y.; Wu, H.; Cheng, H. C.; Yang, S.; Zhu, E. B.; He, Q. Y.; Ding, M. N.; Li, D. H.; Guo, J.; Weiss, N. O. et al. Toward barrier free contact to molybdenum disulfide using graphene electrodes. Nano Lett. 2015, 15, 3030–3034.
Avsar, A.; Vera-Marun, I. J.; Tan, J. Y.; Watanabe, K.; Taniguchi, T.; Neto, A. H. C.; Özyilmaz, B. Air-stable transport in graphene-contacted, fully encapsulated ultrathin black phosphorus-based field-effect transistors. ACS Nano 2015, 9, 4138–4145.
Wang, Y. Y.; Li, J. Z.; Xiong, J. H.; Pan, Y. Y.; Ye, M.; Guo, Y.; Zhang, H.; Quhe, R.; Lu, J. Does the Dirac cone of germanene exist on metal substrates? Phys. Chem. Chem. Phys. 2016, 18, 19451–19456.
Pan, Y. Y.; Wang, Y. Y.; Ye, M.; Quhe, R.; Zhong, H. X.; Song, Z. G.; Peng, X. Y.; Yu, D. P.; Yang, J. B.; Shi, J. J. et al. Monolayer phosphorene–metal contacts. Chem. Mater. 2016, 28, 2100–2109.
Pan, Y. Y.; Li, S. B.; Ye, M.; Quhe, R.; Song, Z. G.; Wang, Y. Y.; Zheng, J. X.; Pan, F.; Guo, W. L.; Yang, J. B. et al. Interfacial properties of monolayer MoSe2–metal contacts. J. Phys. Chem. C 2016, 120, 13063–13070.
Li, Y. C.; Chen, X. B. Dirac fermions in blue-phosphorus. 2D Mater. 2014, 1, 031002.
Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 1994, 50, 17953–17979.
Kresse, G.; Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 1999, 59, 1758–1775.
Kresse, G.; Hafner, J. Ab initio molecular dynamics for liquid metals. Phys. Rev. B 1993, 47, 558–561.
Kresse, J.; Furthmüller G. Efficiency of ab-initio total energy calculations for metals and semiconductors using a planewave basis set. Comput. Mater. Sci. 1996, 6, 15–50.
Monkhorst, H. J.; Pack, J. D. Special points for Brillouin-zone integrations. Phys. Rev. B 1976, 13, 5188–5192.
Kresse, G.; Hafner, J. Ab initio molecular-dynamics simulation of the liquid-metal–amorphous-semiconductor transition in germanium. Phy. Rev. B 1994, 49, 14251–14269.
Perdew, J. P.; Burke, K.; Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 1996, 77, 3865–3868.
Zhong, H. X.; Quhe, R.; Wang, Y. Y.; Ni, Z. Y.; Ye, M.; Song, Z. G.; Pan, Y. Y.; Yang, J. B.; Yang, L.; Lei, M. et al. Interfacial properties of monolayer and bilayer MoS2 contacts with metals: Beyond the energy band calculations. Sci. Rep. 2016, 6, 21786.
Brandbyge, M.; Mozos, J. L.; Ordejón, P.; Taylor, J.; Stokbro, K. Density-functional method for nonequilibrium electron transport. Phys. Rev. B 2002, 65, 165401.
Smith, D. R.; Schultz, S.; Markoš, P.; Soukoulis, C. M. Determination of effective permittivity and permeability of metamaterials from reflection and transmission coefficients. Phys. Rev. B 2002, 65, 195104.
Soler, J. M.; Artacho, E.; Gale, J. D.; García, A.; Junquera, J.; Ordejón, P.; Sánchez-Portal, A. D. The SIESTA method for ab initio order-N materials simulation. J. Phys. : Condens. Matter 2002, 14, 2745–2779.
Çakır, D.; Peeters, F. M. Dependence of the electronic and transport properties of metal-MoSe2 interfaces on contact structures. Phys. Rev. B 2014, 89, 245403.
Cheng, A. H. D.; Cheng, D. T. Heritage and early history of the boundary element method. Eng. Anal. Bound. Elem. 2005, 29, 268–302.
Qiao, J. S.; Kong, X. H.; Hu, Z. X.; Yang, F.; Ji, W. Highmobility transport anisotropy and linear dichroism in few-layer black phosphorus. Nat. Commun. 2014, 5, 4475.
Pan, Y. Y.; Dan, Y.; Wang, Y. Y.; Ye, M.; Zhang, H.; Quhe, R.; Zhang, X. Y.; Li, J. Z.; Guo, W. L.; Yang, L. et al. Schottky barriers in bilayer phosphorene transistors. ACS Appl. Mater. Interfaces 2017, 9, 12694–12705.
Zhang, X. Y.; Pan, Y. Y.; Ye, M.; Quhe, R.; Wang, Y. Y.; Guo, Y.; Dan, Y.; Song, Z. G.; Li, J. Z.; Yang, J. B. et al. Three-layer phosphorene–metal interfaces. Nano Res., inpress, DOI: 10.1007/s12274-017-1680-6.
Pan, Y. Y.; Wang, Y. Y.; Wang, L.; Zhong, H. X.; Quhe, R.; Ni, Z. Y.; Ye, M.; Mei, W. N.; Shi, J. J.; Guo, W. L. et al. Graphdiyne-metal contacts and graphdiyne transistors. Nanoscale 2015, 7, 2116–2127.
Wang, Y. Y.; Yang, R. X.; Quhe, R.; Zhong, H. X.; Cong, L. X.; Ye, M.; Ni, Z. Y.; Song, Z. G.; Yang, J. B.; Shi, J. J. et al. Does p-type Ohmic contact exist in WSe2-metal interfaces? Nanoscale 2016, 8, 1179–1191.
Guo, Y.; Pan, F.; Ye, M.; Wang, Y. Y.; Pan, Y. Y.; Zhang, X. Y.; Li, J. Z.; Zhang, H.; Lu, J. Interfacial properties of stanene–metal contacts. 2D Mater. 2016, 3, 035020.
Guo, Y.; Pan, F.; Ye, M.; Sun, X. T.; Wang, Y. Y.; Li, J. Z.; Zhang, X. Y.; Zhang, H.; Pan, Y. Y.; Song, Z. G. et al. Monolayer bismuthene-metal contacts: A theoretical study. ACS Appl. Mater. Inter. 2017, 9, 23128–23140.
Wang, Y. Y.; Ye, M.; Weng, M. Y.; Li, J. Z.; Zhang, X. Y.; Zhang, H.; Guo, Y.; Pan, Y. Y.; Xiao, L.; Liu, J. K. et al.Electrical contacts in monolayer arsenene devices. ACS Appl.Mater. Interfaces, in press, doi: 10.1021/acsami.7b08513.
So, C.; Zhang, H.; Wang, Y. Y.; Ye, M.; Pan, Y. Y.; Quhe, R.; Li, J. Z.; Zhang, X. Y.; Zhou, Y. S.; Lu, J. A computationalstudy of monolayer hexagonal WTe2 to metal interfaces. Phys. Status Solidi B, in press, DOI: 10.1002/pssb.201600837.
Zeng, J.; Cui, P.; Zhang, Z. Y. Half layer by half layer growth of a blue phosphorene monolayer on a GaN(001) substrate. Phys. Rev. Lett. 2017, 118, 046101.
Heine, V. Theory of surface states. Phys. Rev. 1965, 138, A1689–A1696.
Gong, C.; Colombo, L.; Wallace, R. M.; Cho, K. The unusual mechanism of partial Fermi level pinning at metal-MoS2 interfaces. Nano Lett. 2014, 14, 1714–1720.
Guo, Y. Z.; Liu, D. M.; Robertson, J. 3D behavior of schottky barriers of 2D transition-metal dichalcogenides. ACS Appl. Mater. Interfaces 2015, 7, 25709–25715.
Kim, C.; Moon, I.; Lee, D.; Choi, M. S.; Ahmed, F.; Nam, S.; Cho, Y.; Shin, H. J.; Park, S.; Yoo, W. J. Fermi level pinning at electrical metal contacts of monolayer molybdenum dichalcogenides. ACS Nano 2017, 11, 1588–1596.
Liu, H.; Neal, A. T.; Ye, P. D. Channel length scaling of MoS2 MOSFETs. ACS Nano 2012, 6, 8563–8569.
Das, S.; Appenzeller, J. WSe2 field effect transistors with enhanced ambipolar characteristics. Appl. Phys. Lett. 2013, 103, 103501.
Ling, Z. P.; Sakar, S.; Mathew, S.; Zhu, J. T.; Gopinadhan, K.; Venkatesan, T.; Ang, K. W. Black phosphorus transistors with near band edge contact schottky barrier. Sci. Rep. 2015, 5, 18000.
Du, Y. C.; Liu, H.; Deng, Y. X.; Ye, P. D. Device perspective for black phosphorus field-effect transistors: Contact resistance, ambipolar behavior, and scaling. ACS Nano 2014, 8, 10035–10042.
Lebedeva, I. V.; Lebedev, A. V.; Popov, A. M.; Knizhnik, A. A. Comparison of performance of van der Waals-corrected exchange-correlation functionals for interlayer interaction in graphene and hexagonal boron nitride. Comp. Mater. Sci. 2017, 128, 45–58.
Das, S.; Demarteau, M.; Roelofs, A. Ambipolar phosphorene field effect transistor. ACS Nano 2014, 8, 11730–11738.