3D Behavior of Schottky Barriers of 2D Transition-Metal Dichalcogenides
3D Behavior of Schottky Barriers of 2D Transition-Metal Dichalcogenides
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DOI：
10.1021/acsami.5b06897
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发表时间：
2015-11-25
影响因子：
9.5
通讯作者：
Robertson, John
中科院分区：
文献类型：
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作者：
Guo, Yuzheng;Liu, Dameng;Robertson, John
过渡金属二卤化物(TMD)是层与层之间具有范德华键的二维层状固体。我们用超晶胞模型和密度泛函理论计算了它们的肖特基势垒高度。结果表明，无缺陷的SBH具有很强的钉扎效应，钉扎因子S约为S=0.3，顶接触和边接触的钉扎系数相近。这是因为尽管隔离材料中的层间键合较弱，但对于顶部和边缘接触几何形状，接触金属原子和TMD硫化物原子之间存在直接成键。肖特基势垒在很大程度上遵循金属诱导能带态(MGs)模型，就像三维半导体的模型一样，尽管TMD中的成键在很大程度上被限制在层内。研究发现，边缘接触结构的缝隙钉扎能比顶部接触结构的低，这可能用于在MoS2上获得p型接触。
The transition metal dichalcogenides (TMDs) are two-dimensional layered solids with van der Waals bonding between layers. We calculate their Schottky barrier heights (SBHs) using supercell models and density functional theory. It is found that the SBHs without defects are quite strongly pinned, with a pinning factor S of about S = 0.3, a similar value for both top and edge contact geometries. This arises because there is direct bonding between the contact metal atoms and the TMD chalcogen atoms, for both top and edge contact geometries, despite the weak interlayer bonding in the isolated materials. The Schottky barriers largely follow the metal induced gap state (MIGS) model, like those of three-dimensional semiconductors, despite the bonding in the TMDs being largely constrained within the layers. The pinning energies are found to be lower in the gap for edge contact geometries than for top contact geometries, which might be used to obtain p-type contacts on MoS2.