Enhanced sensitivity of MoSe2 monolayer for gas adsorption induced by electric field
Enhanced sensitivity of MoSe2 monolayer for gas adsorption induced by electric field
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MoSe2单层电场诱导气体吸附的增强灵敏度
DOI：
10.1088/1361-648x/ab29d8
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发表时间：
2019-11-06
影响因子：
2.7
通讯作者：
Shen, Xiaodong
中科院分区：
文献类型：
--
作者：
Ai, Wen;Kou, Liangzhi;Shen, Xiaodong
根据最近的研究，基于MoSe2的气体传感器比基于石墨烯的传感器具有更好的检测性能，特别是对N基气体分子的检测性能，但其原因在微观水平上还没有完全理解。本文用密度泛函理论方法研究了CO、CO_2、NH_3、NO和NO_2气体分子在MoSe_2单分子膜上的吸附。我们的结果表明，MoSe_2单分子膜对含N气体分子的吸附确实比含C气体分子更敏感，这可以归因于气体分子与MoSe_2之间明显的电荷转移。用非平衡态格林函数(NEGF)方法进一步计算了电导。发现NH3和NO2吸附MoSe2的电导降低，这与最近实验中MoSe2对NH3和NO2分子的高灵敏度是一致的。此外，外加电场可以显著提高吸附灵敏度，这意味着MoSe2对气体的检测是可控的。吸附的NO和NO2分子的磁矩也可以被场敏电荷转移有效地调制。我们的结果不仅给出了最近的实验的微观解释，而且还表明MoSe_2作为一种有希望的可控气体传感材料。
According to recent studies, gas sensors based on MoSe2 have better detection performance than graphene-based sensors, especially for N-based gas molecules, but the reason for that is not fully understood at the microscopic level. Here, we investigate the adsorption of CO, CO2, NH3, NO and NO2 gas molecules on MoSe2 monolayer by the density functional theory calculations. Our results reveal that indeed MoSe2 monolayer is more sensitive to adsorption of N-containing gas molecules than C-containing, which can be attributed to the distinct charge transfer between the gas molecules and MoSe2. The conductance was further calculated using the nonequilibrium Green’s function (NEGF) formalism. The reduced conductance was found for NH3 and NO2 adsorbed MoSe2, consistent with the high sensitivity of MoSe2 for NH3 and NO2 molecules in the recent experiments. In addition, the adsorption sensitivity can significantly be improved by an external electric field, which implies the controllable gas detection by MoSe2. The magnetic moments of adsorbed NO and NO2 molecules can also be effectively modulated by the field-sensitive charge transfer. Our results not only give microscopic explanations to the recent experiments, but also suggest using MoSe2 as a promising material for controlled gas sensing.