石墨烯的當今時代變得由A.K Geim執行的突破性發現後知更廣闊的世界海姆和K. Novoselov，而不使用比粘合帶等等。從那時起石墨烯合成變得更加複雜和可靠，​​一路可以合成大面積的，無缺陷的石墨烯的當前化學氣相沉積系統。儘管有這些進步，在石墨烯生長，一個經常被忽視的石墨烯合成過程的一部分，對應於用於去除金屬催化劑存在於CVD生長石墨烯的蝕刻溶液。有一種普遍的共識是石墨烯的葉子在清潔類似，如果不相同的一個生長過程中實現的狀態的蝕刻和轉移過程;而不幸的是這是情況並非如此。在蝕刻和轉移過程的石墨烯不僅收集不必要的外來污染物和雜質，但酸和聚合物通常使用假印記是難以忽視。

為了深入了解這些機制，不同的蝕刻溶液的組合，連同掃描隧道電子顯微鏡（STEM），電子衍射色散譜（EDS）和懸浮的微拉曼被組裝到澄清石墨烯蝕刻如何可以改進和如何一個過程，進入與石墨烯的表面的直接接觸，因為它是蝕刻和轉印葉片可量化和標準化，以便實現一個可靠的石墨烯的工作流程的印記。

The current era of graphene became known to the wider world after the breakthrough discovery performed by A.K. Geim and K. Novoselov without using much more than adhesive tape. Ever since then graphene synthesis has become more sophisticated and reliable, all the way to the current chemical vapor deposition systems which can synthesize large-area, defect-free graphene. Despite all these advancements in graphene growth, an often overlooked part of the graphene synthesis process, corresponding to the etching solutions used to remove the metal catalyst present in CVD grown graphene. There is a general consensus that graphene leaves the etching and transfer process in a state of cleanness similar if not identical to the one achieved during growth; rather unfortunately this is not the case. During etching and transfer processes graphene not only collects unwanted foreign contaminants and dopants but the acids and polymers generally used leave imprints that are hard to ignore.

In order to gain insight into these mechanisms, a combination of different etching solutions, together with scanning tunneling electron microscopy (STEM), electron-diffraction dispersion spectroscopy (EDS) and suspended micro-Raman are assembled to clarify how graphene etching can be improved and how a process that enters in direct contact with graphene surface, as it is etching and transfer leaves imprints that can be quantified and standardized in order to achieve a reliable graphene workflow.

[1] K. S. Novoselov, V. I. Fal’ko, Vladimir Iko, L. Colombo, P. R. Gellert, M. G. Schwab, and K. Kim, “A roadmap for graphene,” Nature, vol. 490, pp. 192–200, 10 2012.
[2] H. W. Kroto, J. R. Heath, S. C. O’Brien, R. F. Curl, and R. E. Smalley, “C60: Buckmin- sterfullerene,” Nature, vol. 318, pp. 162–163, 11 1985.
[3] G. Peters and M. Jansen, “A new fullerene synthesis,” Angewandte Chemie International Edition in English, vol. 31, no. 2, pp. 223–224, 1992.
[4] I. A. Howard, R. Mauer, M. Meister, and F. Laquai, “Effect of morphology on ultra- fast free carrier generation in polythiophene:fullerene organic solar cells,” Journal of the American Chemical Society, vol. 132, pp. 14866–14876, 2014/06/26 2010.
[5] S. Iijima, “Helical microtubules of graphitic carbon,” Nature, vol. 354, pp. 56–58, 11 1991.
[6] J.-L. Li, K. N. Kudin, M. J. McAllister, R. K. Prud’homme, I. A. Aksay, and R. Car, “Oxygen-driven unzipping of graphitic materials,” Phys. Rev. Lett., vol. 96, p. 176101, May 2006.
[7] A. K. Geim and K. S. Novoselov, “The rise of graphene,” Nature Materials, vol. 6, pp. 183–191, 03 2007.
[8] K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science, vol. 306, no. 5696, pp. 666–669, 2004.
79
[9] N. D. Mermin, “Crystalline order in two dimensions,” Physical Review, vol. 176, pp. 250– 254, 12 1968.
[10] K. I. Bolotin, K. J. Sikes, Z. Jiang, M. Klima, G. Fudenberg, J. Hone, P. Kim, and H. L. Stormer, “Ultrahigh electron mobility in suspended graphene,” Solid State Communications, vol. 146, pp. 351–355, 6 2008.
[11] R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim, “Fine structure constant defines visual transparency of graphene,” Science, vol. 320, no. 5881, p. 1308, 2008.
[12] A. A. Balandin, S. Ghosh, W. Bao, I. Calizo, D. Teweldebrhan, F. Miao, and C. N. Lau, “Superior thermal conductivity of single-layer graphene,” Nano Letters, vol. 8, pp. 902– 907, 2014/06/26 2008.
[13] C. Lee, X. Wei, J. W. Kysar, and J. Hone, “Measurement of the elastic properties and intrinsic strength of monolayer graphene,” Science, vol. 321, no. 5887, pp. 385–388, 2008.
[14] X. Li, W. Cai, J. An, S. Kim, J. Nah, D. Yang, R. Piner, A. Velamakanni, I. Jung, E. Tutuc, S. K. Banerjee, L. Colombo, and R. S. Ruoff, “Large-area synthesis of high-quality and uniform graphene films on copper foils,” Science, vol. 324, no. 5932, pp. 1312–1314, 2009.
[15] C.-C. Lu, Y.-C. Lin, Z. Liu, C.-H. Yeh, K. Suenaga, and P.-W. Chiu, “Twisting bilayer graphene superlattices,” ACS Nano, vol. 7, no. 3, pp. 2587–2594, 2013.
[16] Y.-C. Lin, C. Jin, J.-C. Lee, S.-F. Jen, K. Suenaga, and P.-W. Chiu, “Clean transfer of graphene for isolation and suspension,” ACS Nano, vol. 5, no. 3, pp. 2362–2368, 2011.
[17] C.-H. Yeh, H. Medina, C.-C. Lu, K.-P. Huang, Z. Liu, K. Suenaga, and P.-W. Chiu, “Scalable graphite/copper bishell composite for high-performance interconnects,” ACS Nano, vol. 8, no. 1, pp. 275–282, 2014.
80
[18] N. Petrone, I. Meric, J. Hone, and K. L. Shepard, “Graphene field-effect transistors with gigahertz-frequency power gain on flexible substrates,” Nano Letters, vol. 13, no. 1, pp. 121–125, 2013.
[19] S. Reich, J. Maultzsch, C. Thomsen, and P. Ordejón, “Tight-binding description of graphene,” Phys. Rev. B, vol. 66, p. 035412, Jul 2002.
[20] J. C. Slonczewski and P. R. Weiss, “Band structure of graphite,” Phys. Rev., vol. 109, pp. 272–279, Jan 1958.
[21] A. Jorio, R. Saito, M. Dresselhaus, and G. Dresselhaus, Raman Spectroscopy in Graphene Related Systems. Wiley-VCH Verlag GmbH, 2011.
[22] M. I. Katsnelson, K. S. Novoselov, and A. K. Geim, “Chiral tunnelling and the klein paradox in graphene,” Nat Phys, vol. 2, pp. 620–625, 09 2006.
[23] K.S.Novoselov,A.K.Geim,S.V.Morozov,D.Jiang,M.I.Katsnelson,I.V.Grigorieva, S. V. Dubonos, and A. A. Firsov, “Two-dimensional gas of massless dirac fermions in graphene,” Nature, vol. 438, pp. 197–200, 11 2005.
[24] K.S.Novoselov,Z.Jiang,Y.Zhang,S.V.Morozov,H.L.Stormer,U.Zeitler,J.C.Maan, G. S. Boebinger, P. Kim, and A. K. Geim, “Room-temperature quantum hall effect in graphene,” Science, vol. 315, no. 5817, p. 1379, 2007.
[25] K. S. Novoselov, D. Jiang, F. Schedin, T. J. Booth, V. V. Khotkevich, S. V. Morozov, and A. K. Geim, “Two-dimensional atomic crystals,” Proceedings of the National Academy of Sciences of the United States of America, vol. 102, no. 30, pp. 10451–10453, 2005.
[26] G. Gu, S. Nie, R. M. Feenstra, R. P. Devaty, W. J. Choyke, W. K. Chan, and M. G. Kane, “Field effect in epitaxial graphene on a silicon carbide substrate,” Applied Physics Letters, vol. 90, no. 25, pp. –, 2007.
[27] Y. Lee, S. Bae, H. Jang, S. Jang, S.-E. Zhu, S. H. Sim, Y. I. Song, B. H. Hong, and J.-H. 81 Ahn, “Wafer-scale synthesis and transfer of graphene films,” Nano Letters, vol. 10, no. 2, pp. 490–493, 2010. PMID: 20044841.
[28] X. Liu, L. Fu, N. Liu, T. Gao, Y. Zhang, L. Liao, and Z. Liu, “Segregation growth of graphene on cu–ni alloy for precise layer control,” The Journal of Physical Chemistry C, vol. 115, no. 24, pp. 11976–11982, 2011.
[29] A. Reina, X. Jia, J. Ho, D. Nezich, H. Son, V. Bulovic, M. S. Dresselhaus, and J. Kong, “Large area, few-layer graphene films on arbitrary substrates by chemical vapor deposi- tion,” Nano Letters, vol. 9, no. 1, pp. 30–35, 2009.
[30] S.Bae,H.Kim,Y.Lee,X.Xu,J.-S.Park,Y.Zheng,J.Balakrishnan,T.Lei,H.RiKim,Y.I. Song, Y.-J. Kim, K. S. Kim, B. Ozyilmaz, J.-H. Ahn, B. H. Hong, and S. Iijima, “Roll-to- roll production of 30-inch graphene films for transparent electrodes,” Nat Nano, vol. 5, pp. 574–578, 08 2010.
[31] W. Yang, G. Chen, Z. Shi, C.-C. Liu, L. Zhang, G. Xie, M. Cheng, D. Wang, R. Yang, D. Shi, K. Watanabe, T. Taniguchi, Y. Yao, Y. Zhang, and G. Zhang, “Epitaxial growth of single-domain graphene on hexagonal boron nitride,” Nat Mater, vol. 12, pp. 792–797, 09 2013.
[32] C.J.L.delaRosa,J.Sun,N.Lindvall,M.T.Cole,Y.Nam,M.Löffler,E.Olsson,K.B.K. Teo, and A. Yurgens, “Frame assisted h2o electrolysis induced h2 bubbling transfer of large area graphene grown by chemical vapor deposition on cu,” Applied Physics Letters, vol. 102, no. 2, pp. –, 2013.
[33] L. Gao, W. Ren, H. Xu, L. Jin, Z. Wang, T. Ma, L.-P. Ma, Z. Zhang, Q. Fu, L.-M. Peng, X. Bao, and H.-M. Cheng, “Repeated growth and bubbling transfer of graphene with millimetre-size single-crystal grains using platinum,” Nat Commun, vol. 3, p. 699, 02 2012.
[34] Y.-C.Lin,C.-C.Lu,C.-H.Yeh,C.Jin,K.Suenaga,andP.-W.Chiu,“Grapheneannealing: How clean can it be?,” Nano Letters, vol. 12, no. 1, pp. 414–419, 2012.
82
Bibliography
[35] A. C. Ferrari and D. M. Basko, “Raman spectroscopy as a versatile tool for studying the
properties of graphene,” Nat Nano, vol. 8, pp. 235–246, 04 2013.
[36] M. Dresselhaus, A. Jorio, and R. Saito, “Characterizing graphene, graphite, and carbon nanotubes by raman spectroscopy,” Annual Review of Condensed Matter Physics, vol. 1, no. 1, pp. 89–108, 2010.
[37] S. Reich and C. Thomsen, “Raman spectroscopy of graphite,” Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, vol. 362, no. 1824, pp. 2271–2288, 2004.
[38] V. Carozo, C. M. Almeida, E. H. M. Ferreira, L. G. Cançado, C. A. Achete, and A. Jorio, “Raman signature of graphene superlattices,” Nano Letters, vol. 11, no. 11, pp. 4527–4534, 2011.
[39] A. C. Ferrari, “Raman spectroscopy of graphene and graphite: Disorder, electron– phonon coupling, doping and nonadiabatic effects,” Solid State Communications, vol. 143, no. 1–2, pp. 47 – 57, 2007.
[40] S. Pisana, M. Lazzeri, C. Casiraghi, K. S. Novoselov, A. K. Geim, A. C. Ferrari, and F. Mauri, “Breakdown of the adiabatic born-oppenheimer approximation in graphene,” Nat Mater, vol. 6, pp. 198–201, 03 2007.
[41] A. N. Grigorenko, M. Polini, and K. S. Novoselov, “Graphene plasmonics,” Nature Pho- tonics, vol. 6, pp. 749–758, 11 2012.
[42] A. V. Krasheninnikov, P. O. Lehtinen, A. S. Foster, P. Pyykkö, and R. M. Nieminen, “Embedding transition-metal atoms in graphene: Structure, bonding, and magnetism,” Phys. Rev. Lett., vol. 102, p. 126807, Mar 2009.
[43] K. Sengupta and G. Baskaran, “Tuning kondo physics in graphene with gate voltage,” Phys. Rev. B, vol. 77, p. 045417, Jan 2008.
83
Bibliography
[44] K. M. McCreary, K. Pi, and R. K. Kawakami, “Metallic and insulating adsorbates on
graphene,” Applied Physics Letters, vol. 98, no. 19, pp. –, 2011.
[45] Z. Liu, Y.-C. Lin, C.-C. Lu, C.-H. Yeh, P.-W. Chiu, S. Iijima, and K. Suenaga, “In situ observation of step-edge in-plane growth of graphene in a stem,” Nat Commun, vol. 5, 06 2014.
[46] Y.-C. Lin, C.-Y. Lin, and P.-W. Chiu, “Controllable graphene n-doping with ammonia plasma,” Applied Physics Letters, vol. 96, no. 13, pp. –, 2010.
[47] P. Han, Y. Yue, Z. Liu, W. Xu, L. Zhang, H. Xu, S. Dong, and G. Cui, “Graphene oxide nanosheets/multi-walled carbon nanotubes hybrid as an excellent electrocatalytic material towards vo2+/vo2+ redox couples for vanadium redox flow batteries,” Energy Environ. Sci., vol. 4, pp. 4710–4717, 2011.
[48] A. W. Robertson and J. H. Warner, “Atomic resolution imaging of graphene by trans- mission electron microscopy,” Nanoscale, vol. 5, pp. 4079–4093, 2013.
[49] J. H. Warner, Z. Liu, K. He, A. W. Robertson, and K. Suenaga, “Sensitivity of graphene edge states to surface adatom interactions,” Nano Letters, vol. 13, no. 10, pp. 4820–4826, 2013.
[50] P. Koskinen, S. Malola, and H. Häkkinen, “Evidence for graphene edges beyond zigzag and armchair,” Phys. Rev. B, vol. 80, p. 073401, Aug 2009.
[51] C. Casiraghi, A. Hartschuh, H. Qian, S. Piscanec, C. Georgi, A. Fasoli, K. S. Novoselov, D. M. Basko, and A. C. Ferrari, “Raman spectroscopy of graphene edges,” Nano Letters, vol. 9, no. 4, pp. 1433–1441, 2009. PMID: 19290608.
[52] X. Jia, J. Campos-Delgado, M. Terrones, V. Meunier, and M. S. Dresselhaus, “Graphene edges: a review of their fabrication and characterization,” Nanoscale, vol. 3, pp. 86–95, 2011.