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Interfacial Properties for a Monolayer CrS 2 Contact with Metal: A Theoretical Perspective
Author(s) -
Habib Mohammad R.,
Wang Shengping,
Obaidulla Sk M.,
Khan Yahya,
Pi Xiaodong,
Xu Mingsheng
Publication year - 2019
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201800597
Subject(s) - monolayer , density functional theory , schottky barrier , band gap , fermi level , materials science , semiconductor , condensed matter physics , electron , quantum tunnelling , fermi energy , transition metal , nanotechnology , optoelectronics , chemistry , computational chemistry , physics , biochemistry , diode , quantum mechanics , catalysis
Limited calculations show that monolayer (ML) chromium dichalcogenide (CrS 2 ) has a direct bandgap and valley polarization but with a smaller bandgap than ML MoS 2 and with distinct piezoelectric and ferromagnetic properties. It is highly desirable to determine an appropriate metal contact for novel two‐dimensional (2D) CrS 2 ‐based devices. By using density functional theory (DFT), the interface between ML CrS 2 and commonly used metals, including s ‐electron and d ‐electron metals, is studied systematically by evaluating the binding energy, Schottky barrier, orbital overlap, and tunneling barrier at the interfaces. The d ‐electron metals show higher binding energy with the ML CrS 2 than the s ‐electron metals, which is due to the different occupancy and position of the d ‐band of the metals. A strong Fermi level pinning is found in the metal–CrS 2 contacts. Both n‐type and quasi p‐type phenomena for CrS 2 with respect to pristine CrS 2 can be produced at the CrS 2 contacts with the metals. The higher overlap states between the CrS 2 and Ti result in a higher minimum electron density at the Schottky interface, suggesting that Ti is the best contact among the investigated metals for use in CrS 2 ‐based devices for efficient electron injection. The DFT results provide a guideline that is invaluable for experimentally designing novel 2D CrS 2 semiconductor devices.