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TT: Fachverband Tiefe Temperaturen
TT 55: Low-Dimensional Systems: 2D – Theory
TT 55.2: Talk
Wednesday, March 18, 2015, 09:45–10:00, H 3010
First-principles analysis of MoS2/Ti2C and MoS2/Ti2CY2 (Y = F and OH) all-2D semiconductor/metal contacts — •Udo Schwingenschlögl1, Li-Yong Gan1, Yu-Jun Zhao2, and Dan Huang3 — 1KAUST, Thuwal 23955-6900, Saudi Arabia — 2South China University of Technology, Guangzhou 510640, People’s Republic of China — 3Hunan University of Arts and Science, Changde 415000, People’s Republic of China
First-principles calculations are used to explore the geometry, bonding, and electronic properties of MoS2/Ti2C and MoS2/Ti2CY2 (Y = F and OH) semiconductor/metal contacts. The structure of the interfaces is determined. Strong chemical bonds formed at the MoS2/Ti2C interface result in additional states next to the Fermi level, which extend over the three atomic layers of MoS2 and induce a metallic character. The interaction in MoS2/Ti2CY2, on the other hand, is weak and not sensitive to the specific geometry, and the semiconducting nature thus is preserved. The energy level alignment implies weak and strong n-type doping of MoS2 in MoS2/Ti2CF2 and MoS2/Ti2C(OH)2, respectively. The corresponding n-type Schottky barrier heights are 0.85 and 0.26 eV. We show that the MoS2/Ti2CF2 interface is close to the Schottky limit. At the MoS2/Ti2C(OH)2 interface, we find that a strong dipole due to charge rearrangement induces the Schottky barrier. The present interfaces are well suited for application in all-two-dimensional devices.
[1] Phys. Rev. B 87, 245307 (2013).