Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 55: Low-Dimensional Systems: 2D – Theory

TT 55.2: Vortrag

Mittwoch, 18. März 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).