An Intuitive Equivalent Circuit Model for Multilayer Van Der Waals Heterostructures
An Intuitive Equivalent Circuit Model for Multilayer Van Der Waals Heterostructures
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DOI：
10.1109/ted.2018.2851920
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发表时间：
2018-07
影响因子：
3.1
通讯作者：
Abhinandan Borah;Punnu Jose Sebastian;Ankur Nipane;J. Teherani
中科院分区：
文献类型：
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作者：
Abhinandan Borah;Punnu Jose Sebastian;Ankur Nipane;J. Teherani
二维材料堆叠，称为范德华（vdW）异质结构，由于其有趣的电学和光电特性而受到广泛关注。本文提出了一种直观的电路模型，用于描述由任意数量的二维半导体、石墨烯或金属层组成的 vdW 异质结构的面外静电。我们解释了面外能带图和等效电路元件之间的映射。尽管由于每层的量子电容可变、非线性，无法直接求解 n 层结构的电路模型，但本文利用从能带图获得的直觉，提供了单变量的有效解决方案。我们的方法采用费米-狄拉克统计，同时对二维半导体和石墨烯的有限态密度（DOS）进行正确建模。该方法克服了商业 TCAD 工具中出现的困难，例如当结构以非金属材料终止时正确处理 2-D DOS 和模拟边界条件。基于这种方法，我们开发了 2dmatstacks，这是一个在 nanohub.org 上免费提供的开源工具。总的来说，本文使研究人员能够分析、理解和预测复杂 vdW 堆栈中的实验结果。
Stacks of 2-D materials, known as van der Waals (vdW) heterostructures, have gained vast attention due to their interesting electrical and optoelectronic properties. This paper presents an intuitive circuit model for the out-of-plane electrostatics of a vdW heterostructure composed of an arbitrary number of layers of 2-D semiconductors, graphene, or metal. We explain the mapping between the out-of-plane energy band diagram and the elements of the equivalent circuit. Although the direct solution of the circuit model for an n-layer structure is not possible due to the variable, nonlinear quantum capacitance of each layer, this paper uses the intuition gained from the energy band picture to provide an efficient solution in terms of a single variable. Our method employs Fermi–Dirac statistics while properly modeling the finite density of states (DOS) of 2-D semiconductors and graphene. The approach circumvents difficulties that arise in commercial TCAD tools, such as the proper handling of the 2-D DOS and the simulation boundary conditions when the structure terminates with a nonmetallic material. Based on this methodology, we have developed 2dmatstacks, an open-source tool freely available on nanohub.org. Overall, this paper equips researchers to analyze, understand, and predict experimental results in complicated vdW stacks.