石墨烯為一種單層碳原子構成蜂巢狀二維平面的特殊材料，自2004年開始，單層的石墨烯成功地被塊狀的石墨剝離後，近幾年大家開始探索且研發其他更多不同導電特性的二維材料。石墨烯具有獨特的高導電、高導熱以及對光的高敏感性而備受重視。
本研究利用化學溶劑濕式蝕刻法以及氣泡轉移法，以在不影響石墨烯品質的情況下轉移到矽基板，測量石墨烯二維材料的原子振動反應並探討與其基板的交互作用情形，利用偏振拉曼光譜儀系統量測原子振動的偏振狀態。本研究使用不同偏振態的入射光 （圓偏振光、線性偏振光）照射石墨烯樣品，讓石墨烯因在不同基板上的耦合效應不同而破壞了簡併振動帶，因而使得簡併聲子振動比例有所不同，也導致偏振拉曼振動狀態和振動強度的改變。我們更進一步利用石墨烯中簡併聲子振動帶的特性量測到二維材料具有旋光轉換的效應。本研究也將會介紹如何使用偏振程度（Degree of polarization）的算式結合拉曼光譜來了解不同基板上石墨烯原子振動狀態的偏振特性並能夠藉由數值模擬來驗證實驗結果。這些成果及實驗方法將有助於深入研究光與二維材料與基板交互作用，探討更多基本的材料物理特性及未來可能的應用。

Graphene thin layer exhibits remarkable electronic, optical, and mechanical properties, for this reason, it has high scientific interest, and huge potential for a variety of applications. Furthermore, these properties are very sensitive and highly depend on the choice of the substrates. In this study, we perform the wet-etching chemical method and bubbling transfer method. The two methods can transfer monolayer graphene onto the silicon substrate without affecting the quality of graphene, then measure the vibration response of the graphene. Finally, we discuss the interaction between the material and substrates.
Polarized micro-Raman spectroscopy, which can utilize linearly polarized light and circularly polarized light, is a versatile technique that can be used to study not only the vibrational modes of the materials and also the optical coupling between graphene atoms and the different substrates. The Raman G-band in graphene is the most important phonon mode to examine the optical properties, which C-C bond stretching can arise from not only the layer of graphene increasing and also the structure of the substrates. Interestingly, the Raman spectrum of the G band has characteristics for the helicity exchange. In this report, we have studied the optical helicity exchange between graphene and different substrates by calculating the degree of polarization (DoP) via Raman spectra. This study can help to build the understanding for controlling the phonon mode in graphene (the G band) by choosing the different substrates. The obtained experimental results have been verified by numerically simulated helicity analysis. These results provide an important experimental method for studying the light-matter interaction between two-dimensional materials and substrates.

1 Geim, A. K. & Novoselov, K. S. in Nanoscience and technology: a collection of reviews from nature journals 11-19 (World Scientific, 2010).
2 Saito, R., Tatsumi, Y., Huang, S., Ling, X. & Dresselhaus, M. Raman spectroscopy of transition metal dichalcogenides. Journal of Physics: Condensed Matter 28, 353002 (2016).
3 Saito, R., Hofmann, M., Dresselhaus, G., Jorio, A. & Dresselhaus, M. Raman spectroscopy of graphene and carbon nanotubes. Advances in Physics 60, 413-550 (2011).
4 Dresselhaus, M. S., Dresselhaus, G., Saito, R. & Jorio, A. Raman spectroscopy of carbon nanotubes. Physics reports 409, 47-99 (2005).
5 Juang, S. S.-Y. et al. Probing strain on graphene flake using polarized Raman spectroscopy. Applied Surface Science 331, 472-476 (2015).
6 Yoon, D. et al. Strong polarization dependence of double-resonant Raman intensities in graphene. Nano letters 8, 4270-4274 (2008).
7 Singh, V. et al. Graphene based materials: past, present and future. Progress in materials science 56, 1178-1271 (2011).
8 Mueller, N. S. et al. Evaluating arbitrary strain configurations and doping in graphene with Raman spectroscopy. 2D Materials 5, 015016 (2017).
9 Mohiuddin, T. et al. Uniaxial strain in graphene by Raman spectroscopy: G peak splitting, Grüneisen parameters, and sample orientation. Physical Review B 79, 205433 (2009).
10 Malard, L. M., Pimenta, M. A., Dresselhaus, G. & Dresselhaus, M. S. Raman spectroscopy in graphene. Physics Reports 473, 51-87, doi:https://doi.org/10.1016/j.physrep.2009.02.003 (2009).
11 Lazzeri, M., Attaccalite, C., Wirtz, L. & Mauri, F. Impact of the electron-electron correlation on phonon dispersion: Failure of LDA and GGA DFT functionals in graphene and graphite. Physical Review B 78, 081406 (2008).
12 Bissett, M. A., Tsuji, M. & Ago, H. Strain engineering the properties of graphene and other two-dimensional crystals. Physical Chemistry Chemical Physics 16, 11124-11138 (2014).
13 You, Y., Ni, Z., Yu, T. & Shen, Z. Edge chirality determination of graphene by Raman spectroscopy. Applied Physics Letters 93, 163112 (2008).
14 Budde, H. et al. Raman radiation patterns of graphene. ACS nano 10, 1756-1763 (2016).
15 Fowles, G. R. Introduction to modern optics. (Courier Corporation, 1989).
16 Loudon, R. Theory of the resonance Raman effect in crystals. Journal de Physique 26, 677-683 (1965).
17 Tatsumi, Y. & Saito, R. Interplay of valley selection and helicity exchange of light in Raman scattering for graphene and MoS 2. Physical Review B 97, 115407 (2018).
18 Chen, S.-Y., Zheng, C., Fuhrer, M. S. & Yan, J. Helicity-resolved Raman scattering of MoS2, MoSe2, WS2, and WSe2 atomic layers. Nano letters 15, 2526-2532 (2015).
19 Drapcho, S. G. et al. Apparent breakdown of Raman selection rule at valley exciton resonances in monolayer Mo S 2. Physical Review B 95, 165417 (2017).
20 Huang, Y. et al. Nanoelectronic biosensors based on CVD grown graphene. Nanoscale 2, 1485-1488 (2010).
21 Li, X. et al. Large-area synthesis of high-quality and uniform graphene films on copper foils. science 324, 1312-1314 (2009).
22 Novoselov, K. S. et al. Electric field effect in atomically thin carbon films. science 306, 666-669 (2004).
23 Lee, J., Lee, S. & Yu, H. K. Contamination-free graphene transfer from Cu-foil and Cu-thin-film/sapphire. Coatings 7, 218 (2017).
24 Gao, L. et al. Repeated growth and bubbling transfer of graphene with millimetre-size single-crystal grains using platinum. Nature communications 3, 1-7 (2012).
25 Sutter, P., Sadowski, J. T. & Sutter, E. Graphene on Pt (111): Growth and substrate interaction. Physical Review B 80, 245411 (2009).
26 Sutter, P. W., Flege, J.-I. & Sutter, E. A. Epitaxial graphene on ruthenium. Nature materials 7, 406-411 (2008).
27 Wall, M. The Raman spectroscopy of graphene and the determination of layer thickness. Thermo Sci 5, 1-5 (2011).
28 Lee, J.-H., Kim, S. & Seong, M.-J. Circularly polarized Raman study on diamond structure crystals. Journal of the Korean Physical Society 72, 249-253 (2018).