离子凝胶薄膜栅介石墨烯场效应管
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摘要
在石墨烯场效应晶体管栅介结构中引入具有良好电容特性或极化特性的材料可改善晶体管性能.本文采用化学气相沉积制备的石墨烯并以PVDF-[EMIM]TF2N离子凝胶薄膜(ion-gel film)作为介质层制备底栅型石墨烯场效应管(graphene-based field effect transistor, GFET),研究其电学特性以及真空环境和温度对GFET性能的影响.结果表明离子凝胶薄膜栅介石墨烯场效应晶体管表现出良好的电学特性,室温空气环境中,与SiO_2栅介GFET相比, ion-gel膜栅介GFET开关比(J_(on)/J_(off))和跨导(g_m)分别提高至6.95和3.68×10~(–2) mS,而狄拉克电压(V_(Dirac))低至1.3 V;真空环境下ion-gel膜栅介GFET狄拉克电压最低可降至0.4 V;随着温度的升高, GFET的跨导最高可提升至6.11×10~(–2) mS.
Graphene is a kind of two-dimensional material with high light transmittance, high mechanical properties and high carrier mobility. The energy band of graphene can be turned by doping and electric field. Researches on the application of graphene to electronic devices focused on field effect transistors. For improving the performance, one generally improves the fabrication process and device structure, but many researchers chose to change the material or structure of dielectric layer. Ion-gel is a kind of mixture of organic polymer mesh structure with good thermal stability and high dielectric value, prepared by macromolecule organic polymer and ionic salt electrolyte material. With the effect of electric field, cations and anions in ion-gel diffuse to form a double charge layer distribution with a charge layer on the surface of material. This capacitance characteristic is similar to that of traditional capacitor. In this paper, ion-gel(PVDF-[EMIM]TF2 N) film is used as a dielectric layer material to prepare the bottom-gate graphene-based field effect transistor(GFET), which is compared with the GFET with SiO_2 bottom-gate, according to electrical characteristic curves. The effect of the ion-gel film on the transconductance, switching ratio and Dirac voltage of the GFET are analyzed. The effect of the vacuum environment and temperature on the GFET performance with ion-gel film gate are also investigated.The results show that in the room-temperature environment, the switching ratio and transconductance of the ion-gel film gate GFET device increase to 6.95 and 3.68 × 10~(–2) mS, respectively, compared with those of the SiO_2 gate GFET, while the Dirac voltage decreases to 1.3 V. The increase in transconductance and switching ratio of ion-gel film gate GFETs are mainly due to the high capacitance of ion-gel film compared with those of conventional SiO_2 gate dielectrics. There will be more carriers inside the graphene while in the carrier accumulation region of GFET transfer characteristic curve, which makes graphene more conductive. The Dirac voltage of ion-gel film gate GFET can be reduced to 0.4 V in the vacuum environment; as the temperature increases, the transconductance of GFET can increase up to 6.11×10~(–2) mS. The results indicate that the ion-gel film-based graphene field effect transistor shows good electrical properties in serving as high dielectric constant organic dielectric materials.
Graphene is a kind of two-dimensional material with high light transmittance, high mechanical properties and high carrier mobility. The energy band of graphene can be turned by doping and electric field. Researches on the application of graphene to electronic devices focused on field effect transistors. For improving the performance, one generally improves the fabrication process and device structure, but many researchers chose to change the material or structure of dielectric layer. Ion-gel is a kind of mixture of organic polymer mesh structure with good thermal stability and high dielectric value, prepared by macromolecule organic polymer and ionic salt electrolyte material. With the effect of electric field, cations and anions in ion-gel diffuse to form a double charge layer distribution with a charge layer on the surface of material. This capacitance characteristic is similar to that of traditional capacitor. In this paper, ion-gel(PVDF-[EMIM]TF2 N) film is used as a dielectric layer material to prepare the bottom-gate graphene-based field effect transistor(GFET), which is compared with the GFET with SiO_2 bottom-gate, according to electrical characteristic curves. The effect of the ion-gel film on the transconductance, switching ratio and Dirac voltage of the GFET are analyzed. The effect of the vacuum environment and temperature on the GFET performance with ion-gel film gate are also investigated.The results show that in the room-temperature environment, the switching ratio and transconductance of the ion-gel film gate GFET device increase to 6.95 and 3.68 × 10~(–2) mS, respectively, compared with those of the SiO_2 gate GFET, while the Dirac voltage decreases to 1.3 V. The increase in transconductance and switching ratio of ion-gel film gate GFETs are mainly due to the high capacitance of ion-gel film compared with those of conventional SiO_2 gate dielectrics. There will be more carriers inside the graphene while in the carrier accumulation region of GFET transfer characteristic curve, which makes graphene more conductive. The Dirac voltage of ion-gel film gate GFET can be reduced to 0.4 V in the vacuum environment; as the temperature increases, the transconductance of GFET can increase up to 6.11×10~(–2) mS. The results indicate that the ion-gel film-based graphene field effect transistor shows good electrical properties in serving as high dielectric constant organic dielectric materials.
引文
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[2] Novoselov K S, Geim A K, Morozov S V, Jiang D, Zhang Y,Dubonos S V, Grigorieva I V, Firsov A A 2004 Science 306666
[3] Zhang Y, Tang T, Girit C, Hao Z, Martin M C, Zettl A,Crommie M F, Shen Y R, Wang F 2009 Nature 459 820
[4] Park J S, Choi H J 2015 Phys. Rev. B 92 045402
[5] Liu G L, Yang Z H 2018 Acta Phys. Sin. 67 076301(in Chinese)[刘贵立,杨忠华2018物理学报67 076301]
[6] Lemme M C, Echtermeyer T J, Baus M, Kurz H 2007 IEEE Electr. Dev. Lett. 28 282
[7] Frank S 2010 Nat. Nanotechnol. 5 487
[8] Li X L, Wang X R, Zhang L, Lee S, Dai H J 2008 Science319 1229
[9] Echtermeyer T J, Lemme M C, Bolten J, Baus M,Ramsteiner M, Kurz H 2007 Eur. Phys. J. Spec. Top. 148 19
[10] Shih C J, Pfattner R, Chiu Y C, Liu N, Lei T, Kong D, Kim Y, Chou H H, Bae W G, Bao Z 2015 Nano Lett. 15 7587
[11] Fallahazad B, Lee K, Lian G, Kim S, Corbet C M, Ferrer D A, Colombo L, Tutuc E 2012 Appl. Phys. Lett. 100 093112
[12] Wang B, Liddell K L, Wang J, Koger B, Keating C D, Zhu J2014 Nano Res. 7 1263
[13] Wu C Y, Du X W, Zhou L, Cai Q, Jin Y, Tang L, Zhang H G, Hu G H, Jin Q H 2016 Acta Phys. Sin. 65 080701(in Chinese)[吴春艳,杜晓薇,周麟,蔡奇,金妍,唐琳,张菡阁,胡国辉,金庆辉2016物理学报65 080701]
[14] Kim B J, Jang H, Lee S K, Hong B H, Ahn J H, Cho J H2010 Nano Lett. 10 3464
[15] Lee S K,Kim B J, Jang H,Yoon S C,Lee C,Hong B H,Rogers J A, Cho J H, Ahn J H 2011 Nano Lett. 11 4642
[16] Bard A J, Faulkner L R 2002 Electrochemical Methods.Fundamentals and Applications(2nd Ed.)(Weinheim:WILEY-VCH Verlag GmbH)
[17] Cho J H, Lee J, Xia Y, Kim B S, He Y, Renn M J, Lodge T P, Frisbie C D 2008 Nat. Mater. 7 900
[18] Li X, Zhu Y, Cai W, Borysiak M, Han B, Chen D, Piner R D, Colombo L, Ruoff R S 2009 Nano Lett. 9 4359
[19] Kim K S,Zhao Y, Jang H,Lee S Y,Kim J M, Kim K S,Ahn J H, Kim P, Choi J Y, Hong B H 2009 Nature 457 706
[20] Beams R,Novotny L 2015 J. Phys.:Condens. Matter 27 83002
[21] Ryu S, Liu L, Berciaud S, Yu Y J, Liu H, Kim P, Flynn G W, Brus L E 2010 Nano Lett. 10 4944
[22] Yang Y, Brenner K, Murali R 2012 Carbon 50 1727
[23] Jurgen R 2006 Science 313 1057
[24] Robitaille C D, Fauteux D 1986 J. Electrochem. Soc. 133 315
[25] Geim A K, Novoselov K S 2010 The Rise of Graphene(Nanoscience and Technology:A Collection of Reviews from Nature Journals(Singapore:World Scientific)pp 11-19
[26] Gierz I, Riedl C, Starke U, Ast C R, Kern K 2008 Nano Lett.8 4603
[27] Liu H, Liu Y, Zhu D 2011 J. Mater. Chem. 21 3335