论文标题
通过拉曼测量的石墨烯的超低掺杂和局部电荷变化：实验和模拟
Ultra-low doping and local charge variation in graphene measured by Raman: experiment and simulation
论文作者
论文摘要
避免石墨烯的电荷密度变化和杂质对于高质量石墨烯的设备至关重要。在这里，我们使用Raman 2D峰分解来演示一种光学方法，以监视1-25e10 cm-2范围内的电荷密度变化。我们将拉曼特征与静电门控拉曼和传输测量进行比较，以将2D峰分裂与石墨烯上的电荷密度与高精度相关联。我们发现拉曼2D峰分裂和峰面积与电荷密度线性变化，其中较低的电荷密度会导致较大的2D峰分布。我们在各种掺杂条件下模拟拉曼2D光谱，以研究拉曼2D峰和电荷水坑之间的相关性。这些模拟给出了定性协议，并与实验结果达成了一致。我们的工作提供了一种简单且非侵入性的光学方法，用于在制造石墨烯设备之前估算石墨烯的掺杂水平，局部电荷密度变化和运输特性，其精度比以前报道的光学方法高两个数量级。
Avoiding charge density variations and impurities in graphene is vital for high-quality graphene-based devices. Here, we demonstrate an optical method using Raman 2D peak-split to monitor charge density variations in the range 1-25e10 cm-2. We compare Raman signatures with electrostatically gated Raman and transport measurements to correlate the 2D peak-split with the charge density on graphene with high precision. We found that the Raman 2D peak-split and peak areas linearly varies with the charge density, where a lower charge density results in a larger 2D peak-split. We simulate Raman 2D spectra under various doping conditions to study the correlation between Raman 2D peak and charge puddles. These simulations give qualitative agreement with experimental results. Our work provides a simple and non-invasive optical method for estimating the doping level, local charge density variation and transport properties of graphene before fabricating graphene devices, with up to two orders of magnitude higher precision than previously reported optical methods.
