Abstract
Two-dimensional (2D) atomic crystals, such as graphene and transition-metal dichalcogenides, have emerged as a new class of materials with remarkable physical properties1. In contrast to graphene, monolayer MoS2 is a non-centrosymmetric material with a direct energy gap2,3,4,5. Strong photoluminescence2,3, a current on/off ratio exceeding 108 in field-effect transistors6, and efficient valley and spin control by optical helicity7,8,9 have recently been demonstrated in this material. Here we report the spectroscopic identification in a monolayer MoS2 field-effect transistor of tightly bound negative trions, a quasiparticle composed of two electrons and a hole. These quasiparticles, which can be optically created with valley and spin polarized holes, have no analogue in conventional semiconductors. They also possess a large binding energy (~ 20 meV), rendering them significant even at room temperature. Our results open up possibilities both for fundamental studies of many-body interactions and for optoelectronic and valleytronic applications in 2D atomic crystals.
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References
Novoselov, K. S. Nobel lecture: Graphene: Materials in the Flatland. Rev. Mod. Phys. 83, 837–849 (2011).
Mak, K. F., Lee, C., Hone, J., Shan, J. & Heinz, T. F. Atomically thin MoS2: A new direct-gap semiconductor. Phys. Rev. Lett. 105, 136805 (2010).
Splendiani, A. et al. Emerging photoluminescence in monolayer MoS2 . Nano Lett. 10, 1271–1275 (2010).
Li, T. & Galli, G. Electronic properties of MoS2 nanoparticles. J. Phys. Chem. C 111, 16192–16196 (2007).
Lebegue, S. & Eriksson, O. Electronic structure of two-dimensional crystals from ab initio theory. Phys. Rev. B 79, 115409 (2009).
Radisavljevic, B., Radenovic, A., Brivio, J., Giacometti, V. & Kis, A. Single-layer MoS2 transistors. Nature Nanotech. 6, 147–150 (2011).
Mak, K. F., He, K., Shan, J. & Heinz, T. F. Control of valley polarization in monolayer MoS2 by optical helicity. Nature Nanotech. 7, 494–498 (2012).
Zeng, H., Dai, J., Yao, W., Xiao, D. & Cui, X. Valley polarization in MoS2 monolayers by optical pumping. Nature Nanotech. 7, 490–493 (2012).
Cao, T. et al. Valley-selective circular dichroism of monolayer molybdenum disulphide. Nature Commun. 3, 887 (2012).
Kheng, K. et al. Observation of negatively charged excitons X− in semiconductor quantum wells. Phys. Rev. Lett. 71, 1752–1755 (1993).
Huard, V., Cox, R. T., Saminadayar, K., Arnoult, A. & Tatarenko, S. Bound states in optical absorption of semiconductor quantum wells containing a two-dimensional electron gas. Phys. Rev. Lett. 84, 187–190 (2000).
Finkelstein, G., Shtrikman, H. & Bar-Joseph, I. Optical spectroscopy of a two-dimensional electron gas near the metal-insulator transition. Phys. Rev. Lett. 74, 976–979 (1995).
Lee, C. et al. Anomalous lattice vibrations of single- and few-layer MoS2 . ACS Nano 4, 2695–2700 (2010).
Cheiwchanchamnangij, T. & Lambrecht, W. R. L. Quasiparticle band structure calculation of monolayer, bilayer, and bulk MoS2 . Phys. Rev. B 85, 205302 (2012).
Spivak, B., Kravchenko, S. V., Kivelson, S. A. & Gao, X. P. A. Colloquium: Transport in strongly correlated two dimensional electron fluids. Rev. Mod. Phys. 82, 1743–1766 (2010).
Wigner, E. On the interaction of electrons in metals. Phys. Rev. 46, 1002–1011 (1934).
Mattheiss, L. F. Band structures of transition-metal-dichalcogenide layer compounds. Phys. Rev. B 8, 3719–3740 (1973).
Xiao, D., Liu, G-B., Feng, W., Xu, X. & Yao, W. Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides. Phys. Rev. Lett. 108, 196802 (2012).
Ayari, A., Cobas, E., Ogundadegbe, O. & Fuhrer, M. S. Realization and electrical characterization of ultrathin crystals of layered transition-metal dichalcogenides. J. Appl. Phys. 101, 014507 (2007).
Evans, B. L. & Young, P. A. Optical absorption and dispersion in molybdenum disulphide. Proc. R. Soc. Lond. A 284, 402 (1965).
Ruckenstein, A. E. & Schmitt-Rink, S. Many-body aspects of the optical spectra of bulk and low-dimensional doped semiconductors. Phys. Rev. B 35, 7551–7557 (1987).
Stebe, B. & Ainane, A. Ground-state energy and optical-absorption of excitonic trions in two-dimensional semiconductors. Superlattices Microstruct. 5, 545–548 (1989).
Thilagam, A. Two-dimensional charged-exciton complexes. Phys. Rev. B 55, 7804–7808 (1997).
Ohtaka, K. & Tanabe, Y. Theory of the soft-X-ray edge problem in simple metals: Historical survey and recent developments. Rev. Mod. Phys. 62, 929–991 (1990).
Hawrylak, P. Optical properties of a two-dimensional electron gas: Evolution of spectra from excitons to Fermi-edge singularities. Phys. Rev. B 44, 3821–3828 (1991).
Ogawa, T. Quantum states and optical responses of low-dimensional electron-hole systems. J. Phys. Condens. Matter 16, S3567–S3595 (2004).
Ramasubramaniam, A. Large excitonic effects in monolayers of molybdenum and tungsten dichalcogenides. Phys. Rev. B 86, 115409 (2012).
Kuzmenko, A. B. Kramers-Kronig constrained variational analysis of optical spectra. Rev. Scient. Inst. 76, 083108 (2005).
Korn, T., Heydrich, S., Hirmer, M., Schmutzler, J. & Schueller, C. Low-temperature photocarrier dynamics in monolayer MoS2 . Appl. Phys. Lett. 99, 102109 (2011).
Acknowledgements
This research was supported by the National Science Foundation through grants DMR-0907477 and the Research Corporation Scialog Program at Case Western Reserve University; and by the National Science Foundation through grants DMR-1106172 and 1122594 and by the Department of Energy, Office of Basic Energy Sciences through grant DE-FG02-07ER15842 at Columbia University and through grant DE-SC0001085 for optical instrumentation at Columbia University’s Center for Re-Defining Photovoltaic Efficiency through Molecule Scale Control. C.L. acknowledges support from the Korean government Ministry of Education grant Global Frontier Research Center for Advanced Soft Electronics (2011-0031629), and G.H.L. support from Samsung-SKKU Graphene Center.
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K.F.M. and J.S. designed the experiment, performed the measurement and analysis, and prepared the manuscript; K.H. fabricated MoS2 FET devices and measured photoluminescence; C.L. and J.H. developed MoS2 FET devices; G.H.L fabricated MoS2 samples on BN; T.F.H. contributed to the interpretation of the results and writing of the manuscript.
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Mak, K., He, K., Lee, C. et al. Tightly bound trions in monolayer MoS2. Nature Mater 12, 207–211 (2013). https://doi.org/10.1038/nmat3505
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DOI: https://doi.org/10.1038/nmat3505
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