Detection of individual gas molecules adsorbed on graphene
Detection of individual gas molecules adsorbed on graphene
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DOI：
10.1038/nmat1967
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发表时间：
2007-09-01
期刊：
影响因子：
41.2
通讯作者：
Novoselov, K. S.
中科院分区：
文献类型：
--
作者：
Schedin, F.;Geim, A. K.;Novoselov, K. S.
任何检测方法的最终目标都是实现这样一种灵敏度水平，即可以分辨被测实体的单个量子。在化学传感器的情况下，量子是一个原子或分子。到目前为止，这种分辨率超出了任何检测技术的范围，包括因其特殊灵敏度而受到欢迎的固态气体传感器（1-4）。限制这种传感器分辨率的根本原因是由于电荷和缺陷的热运动引起的波动（5），这导致固有噪声超过来自单个分子的所需信号，通常是许多数量级。在这里，我们展示了由石墨烯制成的微米级传感器能够检测气体分子附着在石墨烯表面或从石墨烯表面分离时的单个事件。吸附的分子逐个电子地改变石墨烯中的局部载流子浓度，这导致电阻的阶梯状变化。实现的灵敏度是由于石墨烯是一种电子噪声极低的材料，这使得它不仅成为化学检测器的有希望的候选者，而且也适用于需要对外部电荷，磁场或机械应变敏感的局部探针的其他应用。
The ultimate aim of any detection method is to achieve such a level of sensitivity that individual quanta of a measured entity can be resolved. In the case of chemical sensors, the quantum is one atom or molecule. Such resolution has so far been beyond the reach of any detection technique, including solid-state gas sensors hailed for their exceptional sensitivity(1-4). The fundamental reason limiting the resolution of such sensors is fluctuations due to thermal motion of charges and defects(5), which lead to intrinsic noise exceeding the sought-after signal from individual molecules, usually by many orders of magnitude. Here, we show that micrometre-size sensors made from graphene are capable of detecting individual events when a gas molecule attaches to or detaches from graphene's surface. The adsorbed molecules change the local carrier concentration in graphene one by one electron, which leads to step-like changes in resistance. The achieved sensitivity is due to the fact that graphene is an exceptionally low-noise material electronically, which makes it a promising candidate not only for chemical detectors but also for other applications where local probes sensitive to external charge, magnetic field or mechanical strain are required.