The 2D Debye length: An analytical study of weak charge screening in 2D semiconductors
The 2D Debye length: An analytical study of weak charge screening in 2D semiconductors
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DOI：
10.1063/5.0032541
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发表时间：
2021-01-14
影响因子：
3.2
通讯作者：
Teherani, James T.
中科院分区：
文献类型：
--
作者：
Bechhofer, Adina R.;Ueda, Akiko;Teherani, James T.
二维半导体材料中的简单扰动（例如线电荷或片电荷）由于扰动电荷产生的非均匀面外电场而产生泊松方程的困难解。在这里，第一次，我们确定简单和一般的解析表达式的电位分布，其傅立叶表示，相应的2D德拜屏蔽长度，以及在2D半导体由于线电荷扰动的电荷屏蔽行为。与传统的3D半导体相比，我们发现2D德拜长度为1/ND，2D，其中ND，2D是2D半导体掺杂密度，并且这导致与由传统（3D）德拜长度表达式确定的德拜长度相比明显不同的德拜长度。我们表明，由于在一个2D半导体中的电荷扰动的电位分布不随距离的扰动指数衰减（如3D半导体的情况下），而是在附近的扰动和as 1/x 2时，距离约等于或大于2D德拜长度的grammically衰减。总之，这项工作建立了一个分析方法，用于确定一个基本的静电参数的二维半导体。
Simple perturbations (such as a line charge or a sheet charge) in 2D semiconducting materials create difficult solutions to the Poisson equation due to the non-uniform out-of-plane electric fields that result from the perturbative charge. Here, for the first time, we determine simple and general analytical expressions for the potential profile, its Fourier representation, the corresponding 2D Debye screening length, and the charge screening behavior in 2D semiconductors due to a line charge perturbation. In contrast to conventional 3D semiconductors, we find that the 2D Debye length goes as1 /ND , 2 D, whereND , 2 D is the 2D semiconductor doping density, and this leads to markedly different Debye lengths as compared to those determined by the conventional (3D) Debye length expression. We show that the potential profile due to a charge perturbation in a 2D semiconductor does not decay exponentially with distance from the perturbation (as is the case for 3D semiconductors) but instead decays logarithmically in the immediate vicinity of the perturbation and as1 /x 2 when the distance is approximately equal to or greater than the 2D Debye length. Overall, this work establishes an analytical approach for determining a fundamental electrostatic parameter for 2D semiconductors.