The epitaxial synthesis of molybdenum carbide (Mo2C, a 2D MXene material) via chemical conversion of molybdenum disulfide (MoS2) with thermal annealing under CH4 and H2 is reported. The experimental results show that adjusting the thermal annealing period provides a fully converted metallic Mo2C from MoS2 and an atomically sharp metallic/semiconducting hybrid structure via partial conversion of the semiconducting 2D material. Mo2C/MoS2 hybrid junctions display a low contact resistance (1.2 kω·μm) and low Schottky barrier height (26 meV), indicating the material's potential utility as a critical hybrid structural building block in future device applications. Density functional theory calculations are used to model the mechanisms by which Mo2C grows and forms a Mo2C/MoS2 hybrid structure. The results show that Mo2C conversion is initiated at the MoS2 edge and undergoes sequential hydrodesulfurization and carbide conversion steps, and an atomically sharp interface with MoS2 forms through epitaxial growth of Mo2C. This work provides the area-controllable synthesis of a manufacturable MXene from a transition metal dichalcogenide material and the formation of a metal/semiconductor junction structure. The present results will be of critical importance for future 2D heterojunction structures and functional device applications.
Bibliographical noteFunding Information:
This research was supported by the Global Frontier Program through the Global Frontier Hybrid Interface Materials (GFHIM) (2013M3A6B1078873) of the National Research Foundation of Korea and the Pioneer Research Center Program through the National Research Foundation of Korea funded by the Ministry of Science, ICT & Future Planning (2014M3C1A3053029), and the Basic Science Research Program through the National Research Foundation of Korea funded by the Korean government (MSIP) (grant nos. 2015R1D1A1A09057297, 2015M3A7B7045496, 2016R1A2B4009037, and 2017R1A4A1015400).
© 2018 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physics and Astronomy(all)