그래핀은 sp2 결합으로 이루어진 한 겹의 탄소 물질이며, 그래핀 본래의 우수한 물성으로 인해 다양한 분야에서 활용되고 있다. 그래핀의 높은 전기전도도와 전하이동도로 인해서 (광)전자 소자 물질로 주목받고 있다. 화학적 도핑 과정을 통해 n 형과 p 형의 그래핀이 형성 가능하며 이를 이용하여 다양한 구조의 소자 형성이 가능하게 되었다. 본 연구에서 그래핀의 도핑 효과를 선택적으로 증대시키기 위해 유전영동 현상을 도입하였다. 주파수 10 kHz, 5 Vpp (peakto-peak voltage) 조건에서 유전 영동 현상을 이용하였을 때 금나노입자들이 전극 위치 주변으로 집중됨을 확인하였다. 그래핀의 도핑 효과를 라만 분광법과 전기적 물성 변화를 통하여 조사하였으며, 그래핀에 AuCl3 용액을 이용한 유전영동 현상을 통하여, 그래핀 기반 소자의 국소적인 부분에 선택적으로 화학적 도핑이 가능함을 확인하였다. 이러한 연구는 그래핀 기반 소자와 interconnection 등에 활용될 수 있을 것으로 기대된다.

Graphene is a monolayer carbon material which consists of sp2 bonding between carbon atoms. Its excellent intrinsic properties allow graphene to be used in various research fields. Many researchers believe that graphene is suitable for electronic device materials due to its high electrical conductivity and carrier mobility. Through chemical doping, n- or p-type graphene can be obtained, and consequently graphene-based devices which have more comparable structure to common semiconductor-based devices can be fabricated. In our research, we introduced the dielectrophoresis process to the chemical doping step in order to improve the effect of chemical doping of graphene selectively. Under 10 kHz and 5 Vpp (peak-to-peak voltage), doping was conducted and the Au nanoparticles were effectively formed, as well as aligned along the edges of graphene. Effects of the selective chemical doping on graphene were investigated through Raman spectroscopy and the change of its electrical properties were explored. We proposed the method to enhance the doping effect in local region of a graphene layer.

graphene sheet resistance dielectrophoresis

Bae S, Kim H, Lee Y, Xu XF, Park JS, Zheng Y, Balakrishnan J, Lei T, Kim HR, Song YI, Kim YJ, Kim KS, Ozyilmaz B, Ahn JH, Hong BH, Iijima S, Nat. Nanotechnol., 5(8), 574 (2010)
Bonaccorso F, Sun Z, Hasan T, Ferrari AC, Nat. Photon., 4, 611 (2010)
Mattevi C, Kim H, Chhowalla M, J. Mater. Chem., 21, 3324 (2011)
Bae S, Kim SJ, Shin D, Ahn JH, Hong BH, Phys. Scr., T146, 014024 (2012)
Schedin F, Geim AK, Morozov SV, Hill EW, Blake P, Katsnelson MI, Novoselov KS, Nat. Mater., 6(9), 652 (2007)
Schwierz F, Nat. Nanotechnol., 5(7), 487 (2010)
Liu X, Zhang XW, Meng JH, Yin ZG, Zhang LQ, Wang HL, Wu JL, Appl. Phys. Lett., 106, 233901 (2015)
Miao X, Tongay S, Petterson MK, Berke K, Rinzler AG, Appleton BR, Hebard AF, Nano Lett., 12, 2745 (2012)
Choi BG, Huh YS, Hong WH, Korean Chem. Eng. Res., 50(4), 754 (2012)
Han MY, Ozyilmaz B, Zhang Y, Kim P, Phys. Rev. Lett., 98, 206805 (2007)
Zhou SY, Gweon GH, Fedorov AV, First PN, De Heer WA, Lee DH, Guinea F, Neto AHC, Lanzara A, Nat. Mater., 6(10), 770 (2007)
Guo B, Fang L, Zhang B, Gong JR, Insciences J., 1, 80 (2011)
Fowler JD, Allen MJ, Tung VC, Yang Y, Kaner RB, Weiller BH, ACS nano, 3, 301 (2009)
Pohl HA, J. Appl. Phys., 22, 869 (1951)
Jones TB, Electromechanics of Particles, Cambridge University Press, New York, NY(1995).
Velev OD, Gangwal S, Petsev DN, Annu. Rep. Prog. Chem., Sect. C, 105, 213 (2009)
Lee G, Oh S, Kim BJ, Kim J, ECS Solid State Letters, 3, M41 (2014)
Krupke R, Hennrich F, Lohneysen HV, Kappes MM, Science, 301, 344 (2003)
Kim TH, Lee SY, Cho NK, Seong HK, Choi HJ, Jung SW, Lee SK, Nanotechnology, 17, 3394 (2006)
Vijayaraghavan A, Sciascia C, Dehm S, Lombardo A, Bonetti A, Ferrari AC, Krupke R, ACS Nano, 3, 1729 (2009)
Gierhart BC, Howitt DG, Chen SJ, Smith RL, Collins SD, Langmuir, 23(24), 12450 (2007)
Papadakis SJ, Gu Z, Gracias DH, Appl. Phys. Lett., 88, 233118 (2006)
Ferrari AC, Meyer JC, Scardaci V, Casiraghi C, Lazzeri M, Mauri F, Piscanec S, Jiang D, Novoselov KS, Roth S, Geim AK, Phys. Rev. Lett., 97, 187401 (2006)
Raza H, Graphene Nanoelectronics-Metrology, Synthesis, Properties and Applications, Spinger, Iowa City, Iowa(2012).
Gunes F, Shin HJ, Biswas C, Han GH, Kim ES, Chae SJ, Choi JY, Lee YH, ACS nano, 4, 4595 (2010)
Kim KK, Reina A, Shi Y, Park H, Li LJ, Lee YH, Kong J, Nanotechnology, 21, 285205 (2010)
Kwon KC, Choi KS, Kim SY, Adv. Funct. Mater., 22(22), 4724 (2012)
Schroder DK, Semiconductor material and device characterization, 3rd ed., Wiley Inter-Sciene, Hoboken, NJ(2006).