Characterization of chemical doping of graphene by in-situ Raman spectroscopy
Characterization of chemical doping of graphene by in-situ Raman spectroscopy
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DOI：
10.1063/1.4950969
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发表时间：
2016-05-16
影响因子：
4
通讯作者：
Ahn, Y. H.
中科院分区：
文献类型：
--
作者：
Kim, S. J.;Park, S. J.;Ahn, Y. H.
我们利用原位拉曼光谱研究了浸入硝酸中的单层石墨烯和石墨烯场效应晶体管。在化学掺杂过程中观察到两个不同的阶段。第一阶段涉及G和2D峰的蓝移，其饱和迅速发生，时间常数在10-25s范围内，具体取决于酸的摩尔浓度。在第二阶段，与结构缺陷形成相关的D峰强度在较长时间内增加。由于主要的掺杂效应出现在第一阶段，因此可以通过监测频移来确定没有明显结构缺陷形成的最佳掺杂条件。通过拉曼峰的位置和强度，得到了瞬态掺杂浓度和结构缺陷密度。我们发现石墨烯场效应晶体管中掺杂诱导的Dirac点位移与拉曼光谱中的频率位移有快速响应，这归因于静电门控效应的饱和。AIP出版社出版。
We explored single-layer graphene and graphene field-effect transistors immersed in nitric acid using in-situ Raman spectroscopy. Two distinct stages were observed in the chemical doping process. The first stage involved blue shifts of the G and 2D peaks, whose saturation occurred rapidly with a time constant in the range of 10-25s depending on the molar concentration of the acid. In the second stage, the intensity of the D peak, which was associated with structural defect formation, increased for a relatively long period of time. Since the major doping effects appeared during the first stage, the optimal doping conditions under which no noticeable structural defect formation occurred can be determined by monitoring the frequency shift. Transient doping concentrations along with structural defect densities were obtained from the Raman peak positions and intensities. We found that the doping-induced shift in the Dirac point in graphene field-effect transistors exhibited a fast response with respect to frequency shifts in the Raman spectra, which was attributed to the saturation of electrostatic gating effects. Published by AIP Publishing.