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arXiv 1406.2670cond-mat.mtrl-sci
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磷烯作为一种优良的气体传感器:选择性吸附和独特的I-V响应

Phosphorene as a superior gas sensor: Selective adsorption and distinct I-V response

Liangzhi Kou, Thomas Frauenheim, Changfeng Chen

摘要:

最近关于磷烯制造的报道,即,单层或少层黑磷,提出了一个令人兴奋的前景,一个优秀的二维(2D)材料,表现出优异的性能,纳米器件的应用。本文用第一性原理计算研究了CO、CO_2、NH_3、NO和NO_2气体分子在单层磷烯上的吸附。我们的研究结果预测了磷烯的优越传感性能,可与石墨烯和MoS 2等其他2D材料相媲美甚至超越。我们确定了这些分子在磷烯上的最佳吸附位置,并确定了分子掺杂,即,分子与磷烯之间的电荷转移,作为高吸附强度的驱动机制。我们进一步计算的电流-电压(I-V)的关系,使用非平衡格林函数(NEGF)的形式主义。输运特征在不同方向(扶手椅或锯齿形)上表现出大的(一到两个数量级)各向异性,这与磷烯的各向异性电子能带结构相一致。值得注意的是,I-V关系表现出不同的响应,根据分子的类型,I-V关系沿着扶手椅或锯齿形方向发生显著变化。这种对吸附的选择性和敏感性使得磷烯成为一种优越的气体传感器,有望获得广泛的应用。

英文摘要:

Recent reports on the fabrication of phosphorene, i.e., mono- or few-layer black phosphorus, have raised exciting prospects of an outstanding two-dimensional (2D) material that exhibits excellent properties for nanodevice applications. Here we study by first-principles calculations the adsorption of CO, CO2, NH3, NO and NO2 gas molecules on a mono-layer phosphorene. Our results predict superior sensing performance of phosphorene that rivals or even surpasses other 2D materials such as graphene and MoS2. We determine the optimal adsorption positions of these molecules on the phosphorene and identify molecular doping, i.e., charge transfer between the molecules and phosphorene, as the driving mechanism for the high adsorption strength. We further calculated the current-voltage (I-V) relation using a non-equilibrium Greens function (NEGF) formalism. The transport features show large (one to two orders of magnitude) anisotropy along different (armchair or zigzag) directions, which is consistent with the anisotropic electronic band structure of phosphorene. Remarkably, the I-V relation exhibits distinct responses with a marked change of the I-V relation along either the armchair or the zigzag directions depending on the type of molecules. Such selectivity and sensitivity to adsorption makes phosphorene a superior gas sensor that promises wide-ranging applications.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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