近年來，石墨烯低維度和高電子遷移率特性引起了人們的關注。然而，缺少能隙的特性成為石墨烯在電子元件應用上的障礙。在石墨烯上產生缺陷是調變石墨烯能隙的一種方法。掃描探針微影技術是一種便宜且容易發展的納米尺度技術，可以在石墨烯上局部的產生缺陷。

在我們以前的工作中，我們利用在探針上施加負偏壓，局部的氧化石墨烯。然而，使用掃描探針微影技術的氧化處理的細節尚不清楚。為了理解這一點，我們建構了脈衝掃描探針微影技術系統。這個系統擁有脈衝寬度、位置和輸出阻抗等精確的控制。

藉由這個系統，我們可以製造出點狀陣列，並且用拉曼和原子力顯微鏡測量。這兩種量測都指出這些點狀的缺陷是平均直徑為160nm的孔。而另一方面，藉由調變輸出阻抗而控制的最大電流。我們可以製造出環狀圖案。這明確的指出這些點狀的孔是由充電過程中過大的電流產生的，而少了這個過大的充電電流，環形圖案則是由電壓引起的電解而產生的。綜以上所述，點狀和環狀圖案表示充電過程中電流主導和電壓主導階段。

Graphene has attracted attention in recent years because of low dimensional and high electron mobility. However, the gap-less feature is the main obstacle to further electronic application. Defect generation is one way to manipulate the band gap of graphene. To create defect on graphene, Scanning probe lithography (SPL) is a well-developed nano-meter scale technique. In our previous work, we formed graphene oxidation through negative bias SPL. However, the mechanism of the oxidation processing with SPL is still unveiled. To understand this, we set up a pulsed SPL system with precise pulse width, pulse treatment position control and the output impedance control. After point-like arrays are generated by pulsed SPL, both Raman and atomic force microscopy (AFM) measurements conclude that those defects are holes in average diameter 160 nm on graphene. In the limit of maximum current, ring-like patterns are generated. It indicates that the point-like holes are created by large charging current and that the ring patterns are caused by electrolysis which is driven by voltage. In summary, the point-like and ring-like patterns represent current dominant and voltage dominant phase in the charging process.

[1] Radisavljevic, B. et al. “Single-layer MoS2 transistors” Nature Nanotechnology 6, 147–150 (2011)
[2] Claire Berger et al. “Ultrathin Epitaxial Graphite:  2D Electron Gas Properties and a Route toward Graphene-based Nanoelectronics” . J, Phys. Chem. B, 108 (52), pp 19912–19916 (2004)
[3] K. S. Novoselov1and A. K. Geim et al. “Electric Field Effect in Atomically Thin Carbon Films” Science 22 Vol. 306, Issue 5696, pp. 666-669(2014)
[4] Ponomarenko, L. A. et al. “Chaotic Dirac Billiard in Graphene Quantum Dots” Science 18 Vol. 320, Issue 5874, pp. 356-358 (2008)
[5] Lei Liao et al. “High-speed graphene transistors with a self-aligned nanowire gate” Nature 467, 305–308 (2010)
[6] Raghuraman, Shivaranjan et al. “Driving Surface Chemistry at the Nanometer Scale Using Localized Heat and Stress” Nano Lett., 17 (4), pp 2111–2117 (2017)
[7] Bogdana Borca et al. “Electric-Field-Driven Direct Desulfurization” ACS Nano, 11 (5), pp 4703–4709 (2017)
[8] A. K. Geim, and K. S. Novoselov et al. “The rise of graphene”, Nat.Mater., 6, 183, (2007)
[9] Yung-Chang Lin et al.“Controllable graphene N-doping with ammonia plasma” Appl. Phys. Lett. 96, 133110 (2010)
[10] Zhengtang Luo et al. “Photoluminescence and band gap modulation in graphene oxide” Appl. Phys. Lett. 94, 111909 (2009)
[11] Justin Wu et al. “Controlled Chlorine Plasma Reaction for Noninvasive Graphene Doping” J. Am. Chem. Soc., 133 (49), pp 19668–19671 (2011)
[12] Min-Chiang Chuang et al. “Local anodic oxidation kinetics of chemical vapor deposition graphene supported on a thin oxide buffered silicon template” Carbon Volume 54, Pages 336-342 (2012)
[13] Hsiao-Mei Chien et al. “On the nature of defects created on graphene by scanning probe lithography under ambient conditions” Carbon, Volume 80, Pages 318-324 (2014)
[14] Hung-Chieh Tsai et al. “Graphene reduction dynamics unveiled” 2D Materials, Volume 2, Number 3(2015)
[15] A. H. Castro Neto et al. “The electronic properties of graphene” Rev. Mod. Phys. 81, 109 (2009)
[16] Xuesong Li, Weiwei Cai and Jinho An et al. “Large-Area Synthesis of High-Quality and Uniform Graphene Films on Copper Foils” Science 05 Vol. 324, Issue 5932, pp. 1312-1314 (2009)
[17] Keun Soo Kim et al. “Large-scale pattern growth of graphene films for stretchable transparent electrodes” Nature 457, 706-710 (2009)
[18] G.A.López and E.J.Mittemeijer “The solubility of C in solid Cu” Scripta Materialia Volume 51, Issue 1, pages 1-5 (2004)
[19] Phaedon Avouris, Tobias Hertel, and Richard Martel, “Atomic force microscope tip-induced local oxidation of silicon: kinetics, mechanism, and nanofabrication ”, Phys. Rev. Lett, 71,285 (1997)
[20] DM Eigler, EK Schweizer et al. “Positioning single atoms with a scanning tunnelling microscope” Nature Vol 344 P524-526 (1990)
[21] Ricardo Garcia, Armin W. Knoll & Elisa Riedo “Advanced scanning probe lithography” Nature Nanotechnology 9, 577–587 (2014)
[22] Sacha Gómez-Moñivas et al. “Field-Induced Formation of Nanometer-Sized Water Bridges” Phys. Rev. Lett. 91, 056101(2003)
[23] Narendra Kurra et al. “Nanocarbon-Scanning Probe Microscopy Synergy: Fundamental Aspects to Nanoscale Devices” ACS Appl. Mater. Interfaces 6 (9), pp 6147–6163(2014)
[24] Brandon L. Weeks and Mark W. Vaughn “Direct Imaging of Meniscus Formation in Atomic Force Microscopy Using Environmental Scanning Electron Microscopy” Langmuir, 21 (18), pp 8096–8098(2005)
[25] A. V. Ievlev et al. “Intermittency, quasiperiodicity and chaos in probe-induced ferroelectric domain switching” Nature Physics 10, 59–66 (2014)
[26] Dago, Arancha I., Yu K. Ryu, and Ricardo Garcia. "Sub-20 nm patterning of thin layer WSe2 by scanning probe lithography." Applied Physics Letters 109.16: 163103. (2016)
[27] Kurra, Narendra, Ronald G. Reifenberger, and Giridhar U. Kulkarni. "Nanocarbon-scanning probe microscopy synergy: fundamental aspects to nanoscale devices." ACS applied materials & interfaces 6.9: 6147-6163. (2014)
[28] Lucchese, M.M., Stavale, F., et al ,” Quantifying ion-induced defects and Raman relaxation length in graphene”, Carbon, 48, 1592.(2010)
[29] Malard, L. M., et al. "Raman spectroscopy in graphene." Physics Reports 473.5 (2009): 51-87.
[30] Pimenta, M.A., Dresselhaus, et al,” Studying disorder in Graphite-based systems by Raman spectroscopy”, Phys. Chem. Chem. Phys., 9, 1276, (2007)
[31] Knight, D.S. and White, W.B.,” Characterization of diamond films by Raman spectroscopy ”, J. Mater. Res., 4, 385, (1989)
[32] Kurra, Narendra, et al. "Charge storage in mesoscopic graphitic islands fabricated using AFM bias lithography." Nanotechnology 22.24 245302(2011)