Exploration of channel width scaling and edge states in transition metal dichalcogenides
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We explore the impact of edge states in three types of transition metal dichalcogenides (TMDs), namely metallic Td-phase WTe2 and semiconducting 2H-phase MoTe2 and MoS2, by patterning thin flakes into ribbons with varying channel widths. No obvious charge depletion at the edges is observed for any of these three materials, in contrast to observations made for graphene nanoribbon devices. The semiconducting ribbons are characterized in a three-terminal field-effect transistor (FET) geometry. In addition, two ribbon array designs have been carefully investigated and found to exhibit current levels higher than those observed for conventional one-channel devices. Our results suggest that device structures incorporating a high number of edges can improve the performance of TMD FETs. This improvement is attributed to a higher local electric field, resulting from the edges, increasing the effective number of charge carriers, and the absence of any detrimental edge-related scattering.
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Exploration of channel width scaling and edge states in transition metal dichalcogenides
),
Abstract
We explore the impact of edge states in three types of transition metal dichalcogenides (TMDs), namely metallic Td-phase WTe2 and semiconducting 2H-phase MoTe2 and MoS2, by patterning thin flakes into ribbons with varying channel widths. No obvious charge depletion at the edges is observed for any of these three materials, in contrast to observations made for graphene nanoribbon devices. The semiconducting ribbons are characterized in a three-terminal field-effect transistor (FET) geometry. In addition, two ribbon array designs have been carefully investigated and found to exhibit current levels higher than those observed for conventional one-channel devices. Our results suggest that device structures incorporating a high number of edges can improve the performance of TMD FETs. This improvement is attributed to a higher local electric field, resulting from the edges, increasing the effective number of charge carriers, and the absence of any detrimental edge-related scattering.
References(23)
Das, S.; Chen, H. Y.; Penumatcha, A. V.; Appenzeller, J. High performance multilayer MoS2 transistors with scandium contacts. Nano Lett. 2013, 13, 100–105.
Das, S.; Appenzeller, J. Where does the current flow in twodimensional layered systems? Nano Lett. 2013, 13, 3396–3402.
Das, S.; Appenzeller, J. Screening and interlayer coupling in multilayer MoS2. Phys. Status Solidi RRL 2013, 7, 268–273.
Zhang, F.; Appenzeller, J. Tunability of short-channel effects in MoS2 field-effect devices. Nano Lett. 2015, 15, 301–306.
Pan, H.; Zhang, Y. -W. Edge-dependent structural, electronic and magnetic properties of MoS2 nanoribbons. J. Mater. Chem. 2012, 22, 7280–7290.
Li, Y. F.; Zhou, Z.; Zhang, S. B.; Chen, Z. F. MoS2 nanoribbons: High stability and unusual electronic and magnetic properties. J. Am. Chem. Soc. 2008, 130, 16739–16744.
Li, T. S.; Galli, G. Electronic properties of MoS2 nanoparticles. J. Phys. Chem. C 2007, 111, 16192–16196.
Botello-Méndez, A. R.; López-Urías, F.; Terrones, M.; Terrones, H. Metallic and ferromagnetic edges in molybdenum disulfide nanoribbons. Nanotechnology 2009, 20, 325703.
Ataca, C.; Şahin, H.; Aktürk, E.; Ciraci, S. Mechanical and electronic properties of MoS2 nanoribbons and their defects. J. Phys. Chem. C 2011, 115, 3934–3941.
Bollinger, M. V.; Lauritsen, J. V.; Jacobsen, K. W.; Nørskov, J. K.; Helveg, S.; Besenbacher, F. One-dimensional metallic edge states in MoS2. Phys. Rev. Lett. 2001, 87, 196803.
Liu, H.; Gu, J. J.; Ye, P. D. MoS2 nanoribbon transistors: Transition from depletion mode to enhancement mode by channel-width trimming. IEEE Electron Device Lett. 2012, 33, 1273–1275.
Zhang, C. D.; Johnson, A.; Hsu, C. L.; Li, L. J.; Shih, C. K. Direct imaging of band profile in single layer MoS2 on graphite: Quasiparticle energy gap, metallic edge states, and edge band bending. Nano Lett. 2014, 14, 2443–2447.
Cheng, F.; Xu, H.; Xu, W. T.; Zhou, P. J.; Martin, J.; Loh, K. P. Controlled growth of 1D MoSe2 nanoribbons with spatially modulated edge states. Nano Lett. 2017, 17, 1116–1120.
Nakada, K.; Fujita, M.; Dresselhaus, G.; Dresselhaus, M. S. Edge state in graphene ribbons: Nanometer size effect and edge shape dependence. Phys. Rev. B 1996, 54, 17954–17961.
Miyamoto, Y.; Nakada, K.; Fujita, M. First-principles study of edge states of H-terminated graphitic ribbons. Phys. Rev. B 1999, 59, 9858–9861.
Sui, Y.; Low, T.; Lundstrom, M.; Appenzeller, J. Signatures of disorder in the minimum conductivity of graphene. Nano Lett. 2011, 11, 1319–1322.
Berger, C.; Song, Z. M.; Li, X. B.; Wu, X. S.; Brown, N.; Naud, C.; Mayou, D.; Li, T. B.; Hass, J.; Marchenkov, A. N. et al. Electronic confinement and coherence in patterned epitaxial graphene. Science 2006, 312, 1191–1196.
Han, M. Y.; Özyilmaz, B.; Zhang, Y. B.; Kim, P. Energy band-gap engineering of graphene nanoribbons. Phys. Rev. Lett. 2007, 98, 206805.
Chen, Z. H.; Lin, Y. -M.; Rooks, M. J.; Avouris, P. Graphene nano-ribbon electronics. Phys. E Low Dimens. Syst. Nanostruct. 2007, 40, 228–232.
Lee, C. -H.; Silva, E. C.; Calderin, L.; Nguyen, M. A. T.; Hollander, M. J.; Bersch, B.; Mallouk, T. E.; Robinson, J. A. Tungsten ditelluride: A layered semimetal. Sci. Rep. 2015, 5, 10013.
Mleczko, M. J.; Xu, R. L.; Okabe, K.; Kuo, H. -H.; Fisher, I. R.; Wong, H. S. P.; Nishi, Y.; Pop, E. High current density and low thermal conductivity of atomically thin semimetallic WTe2. ACS Nano 2016, 10, 7507–7514.
Chu, T.; Chen, Z. H. Achieving large transport bandgaps in bilayer graphene. Nano Res. 2015, 8, 3228–3236.
Appenzeller, J.; Zhang, F.; Das, S.; Knoch, J. Transition metal dichalcogenide schottky barrier transistors: A device analysis and material comparison. In 2D Materials for Nanoelectronics, Houssa, M.; Dimoulas, A.; Molle, A., Eds.; CRC Press: Boca Raton, FL, 2016; pp 207–240.
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