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Computational study of hafnium metal contacts to monolayer WSe2.

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Title: Computational study of hafnium metal contacts to monolayer WSe2.
Authors: Feng, Li-ping1 lpfeng@nwpu.edu.cn, Su, Jie1, Liu, Zheng-tang1
Source: Journal of Alloys & Compounds. Aug2015, Vol. 639, p210-214. 5p.
Subjects: Hafnium, Monomolecular films, Tungsten compounds, Density functional theory, Electron transport, Electric properties
Abstract: In this letter, hafnium (Hf) is evaluated as an alternative contact metal to monolayer tungsten diselenide (WSe 2 ) using first-principles plane-wave pseudopotential method based on density functional theory. Four configurations were considered for Hf–WSe 2 top contacts including the bridge, center, top, and upper structures. Results show that Ohmic contact between Hf metal and monolayer WSe 2 is formed and that the electron transport across Hf–WSe 2 top contacts is mainly of a resonant nature. It is found that the arrangements of Hf metal on monolayer WSe 2 play an important role on the energetic and electronic properties of Hf–WSe 2 top contacts. The order of interfacial stability of Hf–WSe 2 top contacts is upper < top < center < bridge, and Hf–WSe 2 top contacts are more stable than Ti–WSe 2 top contact because of their small lattice mismatch. The Hf–WSe 2 top contact with bridge structure has the highest electron density and the lowest tunnel barrier among the four Hf–WSe 2 top contacts. Analysis indicates that Hf metal may be proposed as an alternative electrode material for fabricating top contacts to monolayer WSe 2 due to its good stability and low contact resistance. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
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Abstract:In this letter, hafnium (Hf) is evaluated as an alternative contact metal to monolayer tungsten diselenide (WSe 2 ) using first-principles plane-wave pseudopotential method based on density functional theory. Four configurations were considered for Hf–WSe 2 top contacts including the bridge, center, top, and upper structures. Results show that Ohmic contact between Hf metal and monolayer WSe 2 is formed and that the electron transport across Hf–WSe 2 top contacts is mainly of a resonant nature. It is found that the arrangements of Hf metal on monolayer WSe 2 play an important role on the energetic and electronic properties of Hf–WSe 2 top contacts. The order of interfacial stability of Hf–WSe 2 top contacts is upper < top < center < bridge, and Hf–WSe 2 top contacts are more stable than Ti–WSe 2 top contact because of their small lattice mismatch. The Hf–WSe 2 top contact with bridge structure has the highest electron density and the lowest tunnel barrier among the four Hf–WSe 2 top contacts. Analysis indicates that Hf metal may be proposed as an alternative electrode material for fabricating top contacts to monolayer WSe 2 due to its good stability and low contact resistance. [ABSTRACT FROM AUTHOR]
ISSN:09258388
DOI:10.1016/j.jallcom.2015.03.098