自電晶體被發明以來，半導體產業快速的發展，以滿足人類的需求。然而，到了現今，製程技術的演進已不能只靠微縮元件的能力，還需要引進創新的元件結構或是新穎的奈米材料。
石墨烯為單原子層的薄膜，屬於一種二維結構的材料，擁有許多優異的特性，像是良好的光電特性、導熱特質以及機械性質，近年來成為諸多學者研究的材料。
單層石墨烯自被發現以來，許多製造方法陸續被發表，現今製備大面積成膜石墨烯的方法，主要以熱化學氣相沉積系統，在金屬上成長。然而，高溫與需要轉移限制了石墨烯在工業上的發展，想要將石墨烯應用在元件上，勢必得將其轉移到目標基板上，轉移方法也隨著許多學者的研究而出現。但是目前仍未有一種方法，可以大規模轉移石墨烯，適合讓半導體產業運用在元件製作上。
在這篇論文中，我們會著重在利用電漿輔助化學氣相沉積法，在數分鐘內低溫成長石墨烯，以及利用熱化學氣相沉積法成長免轉移石墨烯。後者的關鍵是在基板上先鍍上金屬，此層金屬除了是成長石墨烯的催化劑，也充當讓石墨烯附著在基板上的犧牲層。後續的分析，我們會以OM、SEM、AFM影像，和Raman spectroscopy的結果，來判斷石墨烯有無成膜及品質的好壞，另外，還會探討製程時間和溫度對石墨烯品質的影響。

In this thesis, we tried to grow graphene by plasma-enhanced chemical vapor deposition (PECVD) at a reduced temperature in several minutes and directly synthesize of transfer-free graphene by thermal CVD. We used optical microscope, scanning electron microscopy, atomic force microscope, and Raman spectroscopy to analysis graphene. We observed whether the graphene is continuous or not and see its quality. In addition, we also experimented on how growth time and temperature affect quality of graphene.
In the experiment growing graphene by PECVD, we used a bell jar covering the copper foil to prevent chamber from being contaminated by copper vapor. The holder we chose with holes can let gas flow pass into the bell jar. Besides, we laid a little holder on this holey holder to make plasma appear in the bell jar. The copper foil was bended so that it could contact the plasma.
The key point of directly synthesizing of transfer-free graphene by thermal CVD is depositing a metal film on substrates in advance. This metal film is not only the catalyst of growing graphene but also a sacrifice layer to make graphene attach to substrates.
We succeed in growing multi-layer graphene by PECVD at temperature between 600 and 700 Celsius degrees in about 10 minutes and directly synthesizing of transfer-free graphene on non-metallic substrates by thermal CVD.

1. Novoselov, K.S., et al., Electric field effect in atomically thin carbon films. Science, 306(5696): p. 666-669, 2004.
2. Singh, V., et al., Graphene based materials: past, present and future. Progress in materials science, 56(8): p. 1178-1271, 2011.
3. Berger, C., et al., Electronic confinement and coherence in patterned epitaxial graphene. Science, 312(5777): p. 1191-1196, 2006.
4. De Heer, W.A., et al., Epitaxial graphene. Solid State Communications, 143(1): p. 92-100, 2007.
5. Hass, J., W. De Heer, and E. Conrad, The growth and morphology of epitaxial multilayer graphene. Journal of Physics: Condensed Matter, 20(32): p. 323202, 2008.
6. Li, X., et al., Highly conducting graphene sheets and Langmuir–Blodgett films. Nature nanotechnology, 3(9): p. 538-542, 2008.
7. Eda, G., G. Fanchini, and M. Chhowalla, Large-area ultrathin films of reduced graphene oxide as a transparent and flexible electronic material. Nature nanotechnology, 3(5): p. 270-274, 2008.
8. Yu, Q., et al., Graphene segregated on Ni surfaces and transferred to insulators. Applied Physics Letters, 93(11): p. 113103, 2008.
9. Li, X., et al., Large-area synthesis of high-quality and uniform graphene films on copper foils. Science, 324(5932): p. 1312-1314, 2009.
10. Li, X., et al., Large-area graphene single crystals grown by low-pressure chemical vapor deposition of methane on copper. Journal of the American Chemical Society, 133(9): p. 2816-2819, 2011.
11. Obraztsov, A., et al., Chemical vapor deposition of thin graphite films of nanometer thickness. Carbon, 45(10): p. 2017-2021, 2007.
12. Kumar, A., et al., Rapid synthesis of few-layer graphene over Cu foil. Carbon, 50(4): p. 1546-1553, 2012.
13. Boyd, D., et al., Single-step deposition of high-mobility graphene at reduced temperatures. Nature communications, 6, 2015.
14. Li, X., et al., Synthesis, characterization, and properties of large-area graphene films. ECS Transactions, 19(5): p. 41-52, 2009.
15. Li, X., et al., Transfer of large-area graphene films for high-performance transparent conductive electrodes. Nano letters, 9(12): p. 4359-4363, 2009.
16. Suk, J.W., et al., Transfer of CVD-grown monolayer graphene onto arbitrary substrates. ACS nano, 5(9): p. 6916-6924, 2011.
17. Juang, Z.-Y., et al., Graphene synthesis by chemical vapor deposition and transfer by a roll-to-roll process. Carbon, 48(11): p. 3169-3174, 2010.
18. Regan, W., et al., A direct transfer of layer-area graphene. Applied Physics Letters, 96(11): p. 113102, 2010.
19. Chen, X.-D., et al., High-quality and efficient transfer of large-area graphene films onto different substrates. Carbon, 56: p. 271-278, 2013.
20. Ni, Z., et al., Graphene thickness determination using reflection and contrast spectroscopy. Nano letters, 7(9): p. 2758-2763, 2007.
21. Blake, P., et al., Making graphene visible. Applied Physics Letters, 91(6): p. 063124, 2007.
22. Jung, I., et al., Simple approach for high-contrast optical imaging and characterization of graphene-based sheets. arXiv preprint arXiv:0706.0029, 2007.
23. Girit, Ç.Ö., et al., Graphene at the edge: stability and dynamics. science, 323(5922): p. 1705-1708, 2009.
24. Gómez-Navarro, C., et al., Atomic structure of reduced graphene oxide. Nano letters, 10(4): p. 1144-1148, 2010.
25. Meyer, J.C., et al., Direct imaging of lattice atoms and topological defects in graphene membranes. Nano letters, 8(11): p. 3582-3586, 2008.
26. Vlassiouk, I., et al., Role of hydrogen in chemical vapor deposition growth of large single-crystal graphene. ACS nano, 5(7): p. 6069-6076, 2011.
27. Paredes, J.I., et al., Atomic force and scanning tunneling microscopy imaging of graphene nanosheets derived from graphite oxide. Langmuir, 25(10): p. 5957-5968, 2009.
28. Malard, L., et al., Raman spectroscopy in graphene. Physics Reports, 473(5): p. 51-87, 2009.
29. Reich, S. and C. Thomsen, Raman spectroscopy of graphite. Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, 362(1824): p. 2271-2288, 2004.
30. Ferrari, A.C., et al., Raman spectrum of graphene and graphene layers. Physical review letters, 97(18): p. 187401, 2006.
31. Ismach, A., et al., Direct chemical vapor deposition of graphene on dielectric surfaces. Nano letters, 10(5): p. 1542-1548, 2010.
32. Su, C.-Y., et al., Direct formation of wafer scale graphene thin layers on insulating substrates by chemical vapor deposition. Nano letters, 11(9): p. 3612-3616, 2011.
33. Yamada, J., et al., Direct growth of multilayer graphene by precipitation using W capping layer. Japanese Journal of Applied Physics, 55(10): p. 100302, 2016.
34. Othman, M., et al., Low-temperature plasma-enhanced chemical vapour deposition of transfer-free graphene thin films. Materials Letters, 158: p. 436-438, 2015.