Probing Strain and Doping along a Graphene Wrinkle Using Tip-Enhanced Raman Spectroscopy
Probing Strain and Doping along a Graphene Wrinkle Using Tip-Enhanced Raman Spectroscopy
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DOI：
10.1021/acs.jpcc.2c08529
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发表时间：
2023-03
期刊：
影响因子：
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通讯作者：
Maria Vanessa Balois-Oguchi;N. Hayazawa;Satoshi Yasuda;K. Ikeda;Tien Quang Nguyen;M. C. Escaño;Takuo Tanaka
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文献类型：
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作者：
Maria Vanessa Balois-Oguchi;N. Hayazawa;Satoshi Yasuda;K. Ikeda;Tien Quang Nguyen;M. C. Escaño;Takuo Tanaka
在化学气相沉积过程中，褶皱是石墨烯生长过程中不可避免的副产品。它们的形成是因为石墨烯和底层衬底的热膨胀系数不同。众所周知，微米级的皱纹会影响石墨烯的电子性能，因为它们的形状和它们产生的应变变化。然而，随着石墨烯在纳米器件中得到更多的应用，有必要研究纳米尺度皱纹的物理和电子性质。在这里，我们使用尖端增强拉曼光谱(TERS)分析了环境条件下宽度为1.9 nm的石墨烯褶皱的应变分布和掺杂。我们通过石墨烯拉曼峰的TERS映射对皱纹进行了成像，发现沿着皱纹的长度发生了各向异性应变和不同的p掺杂。此外，我们还绘制了金(111)的电子拉曼散射(ERS)图，在拉曼光谱中表现为一个宽广的背景连续谱。我们发现石墨烯褶皱的TERS图像与Au(111)衬底的ERS图像之间存在很强的相关性。我们的工作表明，我们可以用TERS详细地探索和研究纳米级特征的物理和电学性质，这对于纳米器件的表征是必不可少的。
Wrinkles are unavoidable byproducts of graphene growth during chemical vapor deposition. They form because of the different thermal expansion coefficients of graphene and the underlying substrate. Micrometer-sized wrinkles are known to affect the electronic properties of graphene due to their shape and the strain variations they create. However, as graphene finds more applications in nanoscale devices, it is necessary to investigate the physical and electronic nature of wrinkles of nanometer dimensions. Here, we analyze the strain distribution and doping of a graphene wrinkle having 1.9 nm width using tip-enhanced Raman spectroscopy (TERS) in ambient conditions. We imaged the wrinkle through TERS mapping of the graphene Raman peaks and found that anisotropic strain and varying p-doping occur along the length of the wrinkle. Furthermore, we mapped the electronic Raman scattering (eRS) from the Au(111) that manifests as a broad background continuum in the Raman spectra. We found a strong correlation between the TERS images of the graphene wrinkle and the eRS of the Au(111) substrate. Our work demonstrates that the as-fabricated physical and electronic properties of nanometer-sized features, such as wrinkles, can be probed and studied in detail with TERS which is essential for nanodevice characterization.