Schottky Barriers in Bilayer Phosphorene Transistors
Schottky Barriers in Bilayer Phosphorene Transistors
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双层磷烯晶体管中的肖特基势垒
DOI：
10.1021/acsami.6b16826
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Jing Lu
中科院分区：
文献类型：
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作者：
Yuanyuan Pan;Yang Dan;Yangyang Wang;Meng Ye;Han Zhang;Ruge Quhe;Xiuying Zhang;Jingzhen Li;Wanlin Guo;Li Yang;Jing Lu
由于费米能级钉扎的存在，用功函数近似法计算具有强相互作用电极的单层（ML）二维材料场效应晶体管（FET）的肖特基势垒高度（SBH）是不可靠的。在这里，我们报告的第一个系统的研究双层（BL）磷烯FET接触的一系列金属具有广泛的功函数范围（Al，Ag，Cu，Au，Cr，Ti，Ni和Pd），通过使用从头计算电子能带计算和量子输运模拟（QTS）。与ML磷烯FET中仅识别出一种类型的肖特基势垒（SB）不同，BL磷烯FET中识别出两种类型的SB：金属化和完整磷烯层之间的垂直SB，其高度由能带分析（EBA）确定;金属化和沟道BL磷烯之间的横向SB，其高度由QTS确定。与流行的WFA相比，来自QTS的ML磷烯FET的垂直SBH与横向SBH显示出更好的一致性。因此，我们开发了一个更好的和更普遍的方法比WFA估计的ML半导体晶体管的横向SBH的强烈相互作用的电极的基础上，其BL对应的EBA。在QTS方面，在BL磷烯与Cr、Al和Cu电极之间形成n型横向肖特基接触，电子SBH分别为0.27、0.31和0.32 eV，而在BL磷烯与Pd、Ti、Ni、Ag和Au电极之间形成p型横向肖特基接触，空穴SBH分别为0.11、0.18、0.19、0.20和0.32 eV。和0.21eV。理论极性和SBH与现有的实验结果吻合得很好。我们的研究提供了一个深入的BL磷烯-金属界面，是设计BL磷烯器件的关键。
It is unreliable to evaluate the Schottky barrier height (SBH) in monolayer (ML) 2D material field effect transistors (FETs) with strongly interacted electrode from the work function approximation (WFA) because of existence of the Fermi-level pinning. Here, we report the first systematical study of bilayer (BL) phosphorene FETs in contact with a series of metals with a wide work function range (Al, Ag, Cu, Au, Cr, Ti, Ni, and Pd) by using both ab initio electronic band calculations and quantum transport simulation (QTS). Different from only one type of Schottky barrier (SB) identified in the ML phosphorene FETs, two types of SBs are identified in BL phosphorene FETs: the vertical SB between the metallized and the intact phosphorene layer, whose height is determined from the energy band analysis (EBA); the lateral SB between the metallized and the channel BL phosphorene, whose height is determined from the QTS. The vertical SBHs show a better consistency with the lateral SBHs of the ML phosphorene FETs from the QTS compared than that of the popular WFA. Therefore, we develop a better and more general method than the WFA to estimate the lateral SBHs of ML semiconductor transistors with strongly interacted electrodes based on the EBA for its BL counterpart. In terms of the QTS,n-type lateral Schottky contacts are formed between BL phosphorene and Cr, Al, and Cu electrodes with electron SBH of 0.27, 0.31, and 0.32 eV, respectively, whilep-type lateral Schottky contacts are formed between BL phosphorene and Pd, Ti, Ni, Ag, and Au electrodes with hole SBH of 0.11, 0.18, 0.19, 0.20, and 0.21 eV, respectively. The theoretical polarity and SBHs are in good agreement with available experiments. Our study provides an insight into the BL phosphorene–metal interfaces that are crucial for designing the BL phosphorene device.