Controlling the electronic and geometric structures of 2D insertions to realize high performance metal/insertion-MoS2 sandwich interfaces.
Controlling the electronic and geometric structures of 2D insertions to realize high performance metal/insertion-MoS2 sandwich interfaces.
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DOI：
10.1039/c7nr00720e
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发表时间：
2017-06
期刊：
影响因子：
6.7
通讯作者：
J. Su;Li-ping Feng;Wei Zeng;Zheng-tang Liu
中科院分区：
文献类型：
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作者：
J. Su;Li-ping Feng;Wei Zeng;Zheng-tang Liu
金属/插入-MoS_2三明治界面设计用于降低金属-MoS_2界面的肖特基势垒。用第一性原理计算方法比较研究了二维插入材料的几何结构和电子结构对金属/插入-MoS_2界面接触性质的影响。无论2D插入材料的几何结构和电子结构如何，由于插入层和MoS2层之间的弱相互作用，没有能隙状态，MoS2层的结构变形可以忽略不计，金属/插入-MoS_2界面的费米能级钉扎效应和电荷散射都被削弱。金属/插入-MoS_2界面的肖特基势垒是由二维插入材料的电荷转移和结构形变决定的三个界面偶极子和四个电势阶跃引起的。2D插入材料的电子亲合势越低，从Sc表面损失的电子就越多，导致Sc/Insertion-MoS_2界面的n型肖特基势垒降低。2D插入材料的电离势越大，厚度越薄，在铂表面积累的电子就越少，从而导致铂/插入-MoS_2界面的p型肖特基势垒降低。所有SC/插入-MoS2接口都表现出欧姆特性。由于最大的电离势(∼6.88 eV)和最薄的BN厚度(单原子层厚度)，Pt/BN-MoS_2界面显示出最低的p型肖特基势垒，为0.52eV。这些结果对理解和设计高性能的金属/插入-MoS_2二维插入材料界面具有一定的参考价值。
Metal/insertion-MoS2 sandwich interfaces are designed to reduce the Schottky barriers at metal-MoS2 interfaces. The effects of geometric and electronic structures of two-dimensional (2D) insertion materials on the contact properties of metal/insertion-MoS2 interfaces are comparatively studied by first-principles calculations. Regardless of the geometric and electronic structures of 2D insertion materials, Fermi level pinning effects and charge scattering at the metal/insertion-MoS2 interface are weakened due to weak interactions between the insertion and MoS2 layers, no gap states and negligible structural deformations for MoS2 layers. The Schottky barriers at metal/insertion-MoS2 interfaces are induced by three interface dipoles and four potential steps that are determined by the charge transfers and structural deformations of 2D insertion materials. The lower the electron affinities of 2D insertion materials, the more are the electrons lost from the Sc surface, resulting in lower n-type Schottky barriers at Sc/insertion-MoS2 interfaces. The larger the ionization potentials and the thinner the thicknesses of 2D insertion materials, the fewer are the electrons that accumulate at the Pt surface, leading to lower p-type Schottky barriers at Pt/insertion-MoS2 interfaces. All Sc/insertion-MoS2 interfaces exhibited ohmic characters. The Pt/BN-MoS2 interface exhibits the lowest p-type Schottky barrier of 0.52 eV due to the largest ionization potential (∼6.88 eV) and the thinnest thickness (single atomic layer thickness) of BN. These results in this work are beneficial to understand and design high performance metal/insertion-MoS2 interfaces through 2D insertion materials.