本研究利用氧氣電漿和化學液蝕刻HFCVD摻錋多晶鑽石，成功的開發出高場發射電流密度35mA/cm2 (at 8.5 V/μm)和低啟動電場4.3 V/μm ( at 10 μA/cm2)的一維次微米鑽石柱林。實驗利用RF射頻13.56 MHz的氧氣電漿系統，功率100W下進行不同時間，不同腔體壓力和不同偏壓大小的蝕刻。最後利用其中最佳參數(壓力15mtorr、功率100W、偏壓-1300V、時間6小時蝕刻的試片再以氯化氫液(HCl37%)在温度90℃下進行30分鐘的溼式蝕刻，接著以銅電極間距100μm、壓力10-6 torr 真空下量測場發射特性。
實驗結果顯示，隨著氧電漿蝕刻時間的增加，鑽石柱林之長度隨著變長，場發射性質因而得到改善。當提升電漿自行偏壓由-1000V到-1300V時，鑽石柱林長度(直徑)由4.2μm（420 nm）變為4.8μm（370 nm），場發射性質也得到改善。接著利用氯化氫液將鑽石柱表面因不鏽鋼生成的Fe2O3蝕刻清除後，鑽石由柱狀變為尖部呈細絲的錐狀，場發性質得到顯著提升，在相同電場8.5 V/μm下場發電流密度由1 mA/cm2提升到35mA/cm2，啟動電場自6 V/μm降至4.3 V/μm ( at 10 μA/cm2)。場發射穩定度方面，一開始出現一穩定區，之後電流密度隨時間快速下降，最終趨於飽和。隨著初始電流密度的增加，穩定區的生命期變短，施加電場越大者表現出越快達到飽和的現象。

One-dimensional boron-doped sub-micron diamond rods (SDRs) with excellent field emission current density 35mA/cm2 (at 8.5 V/μm) and turn on field 4.3 V/μm ( at 10 μA/cm2)are fabricated on polycrystalline diamond/Si by oxygen plasma etching and subsequent HCl etching. SDRs are fabricated on the polycrystalline diamond/Si substrate, made from HFCVD, by using oxygen plasma etching in capacitance coupled plasma (CCP) chamber operated at a radio frequency (RF) of 13.56 MHz. The RF power source is operated at 100 W. The total oxygen gas pressure is kept at 15 mtorr and the self-bias voltage is -1300 V during etching. The one-dimensional SDRs are further wet-etched by HCl(37%) at 90℃for 30 minutes. Field emission properties are measured at 10-6 torr with a spacing of 100μm between the copper anode and cathode.
Experimental results indicate that field emission characteristics are better for longer SDRs. The SDRs’ length (diameter) change from 4.2μm (420nm) to 4.8μm (370nm) as the plasma self-bias voltage increase from -1000V to -1300V, associate with better field emission characteristics. Nevertheless, the as-etched SDRs suffer with high turn-on field (ETO) and low field emission current density (JFE) due to residual iron oxide on the rods’ surfaces. A huge improvement in the field emission characteristics can be achieved by removing iron oxide using a wet-etch process in a diluted HCl (37%). After the wet-etch, field emission current density (JFE) increases from 1 mA/cm2 to 35mA/cm2 under the same filed 8.5 V/μm and turn-on field (ETO) reduces from 6V/μm to 4.3 V/μm ( at 10 μA/cm2). Stability test shows a stable period exists in the beginning and after that the current density decay significantly and approach saturation at last. The stable period become smaller and the near saturation time become shorter with increasing applied field.

[1] R.H. Fowler, et al., "Electron Emission in Intense Elextric Fields," Proc. Roy. Soc. Lond. , vol. A119 , 173., 1928.
[2] C. A. Spind, "A Thin-Film Field-Emission Cathode," J. Appl. Phys. 39, 3504, 1968.
[3] A. A. Talin, et al., "Field emission displays: a critical review," Solid-State Electronics, vol. 45, pp. 963-976, 2001.
[4] J. A. Hart, et al., "A History of Field Emission Displays," 1999.
[5] N. S. Xu and S. E. Huq, "Novel cold cathode materials and applications," Materials Science and Engineering: R: Reports, vol. 48, pp. 47-189, 2005.
[6] http://www.boe.com.cn/, 各類Display特性介紹
[7] 楊素華藍慶忠, "奈米碳管場發射顯示器," 科學發展, vol. 年10月, 328期, 2004.
[8] 陳婷婷碩士論文, "Field emission characteristics of B-doped Diamond Nanotube Fabricated by Oxygen Plasma Etching," 2010.
[9] http://en.wikipedia.org/wiki/Flat_panel_display, 2011.
[10] A. Wisitsorat-at, "Micropatterned Diamond Vacuum Field Emission Devices," 2002.
[11] Takahiro Fusayasu, et al., "Development of a Microdisplay Based on the Field Emission Display Technology," LNCS vol. 3824, pp. 1036-1044, 2005.
[12] R. S. Sussmann(editor), "CVD Diamond for Elextronic Devices and Sensors," Wiley Series in Materials for Electronic and Optoelectronic Applications, 2009.
[13] A. Wisitsora-at, et al., "Efficient electron emitter utilizing boron-doped diamond tips with sp2 content," Applied Surface Science, vol. 146, pp. 280-286, 1999.
[14] S. J. Kang, et al., "Work-function engineering of carbon nanotube transparent conductive films," Carbon, vol. 48, pp. 520-524, 2010.
[15] Walt A. de Heer, et al., "A Carbon Nanotube Field-Emission Electron Source " Science, vol. 270, p. 1179, 1995.
[16] F. Buonocore, et al., "Ab initio calculations of electron afinity and ionization potential of carbon nanotubes," Nanotechnology, vol. 19, p. 25711, 2008.
[17] Young-Jun Yu, et al., "Tuning the Graphene Work Function by Electric Field Effect," Nano letters, vol. 9, p. 3430, 2009.
[18] C. Pennetta, "Work Function and Energy Levels of Positrons in Crystalline Silicon," Solid State Communications, vol. 77, p. 159, 1991.
[19] P. K. Baumann and R. J. Nemanich, "Negative Electron-Affinity Effects on H-Plasma Exposed Diamond(100) Surfaces," Diamond and Related Materials, vol. 4, pp. 802-805, May 1995.
[20] F. Maier, et al., "Electron affinity of plasma-hydrogenated and chemically oxidized diamond (100) surfaces," Physical Review B, vol. 64, p. 165411, 2001.
[21] C. Kim, et al., "Electronic structures of capped carbon nanotubes under electric fields," Physical Review B, vol. 65, p. 165418, 2002.
[22] O. Pulci, et al., "Electronic and optical properties of group IV two-dimensional materials," Phys. Status Solidi A, vol. 207, p. 291, 2010.
[23] V. V. Zhirnov, et al., "Wide band gap materials for field emission devices," J. Vac. Sci. Technol. A vol. 15, p. 1773, 1997.
[24] V. N. Popov, "Carbon nanotubes: properties and application," Materials Science and Engineering: R: Reports, vol. 43, pp. 61-102, 2004.
[25] http://www.wikipedia.org/, 2011.
[26] S. Iijima, "Helical Microtubules of Grephitic Carbon," Nature, vol. 354, pp. 56-58, Nov 1991.
[27] E. Thostenson, et al., "Nanocomposites in context," Composites Science and Technology 65 (3–4): 491–516, 2005.
[28] T. Guo, et al., "Catalytic growth of single-walled manotubes by laser vaporization," Chemical Physics Letters, vol. 243, pp. 49-54, 1995.
[29] W. Zhu, et al., "Large current density from carbon nanotube field emitters," Applied Physics Letters, vol. 75, p. 873, 1999.
[30] J. Kong, et al., "Synthesis of individual single-walled carbon nanotubes on patterned silicon wafers," Nature, vol. 395, pp. 878-881, 1998.
[31] W. Z. Li, et al., "Large-Scale Synthesis of AlignedCarbon Nanotubes," Science, vol. 274, p. 1701, 1996.
[32] Xueshen Wang, et al., "Fabrication of Ultralong and Electrically Uniform Single-Walled Carbon Nanotubes on Clean Substrates," Nano letters, vol. 9, pp. 3137-3141, 2009.
[33] Q. H. Wang, et al., "A nanotube-based field-emission flat panel display," vol. 72, p. 2912, 1998.
[34] R. Z. Junqing Hu*, Yangang Sun and Zhigang Chen, "Excellent Field Emitters: Onion-Shaped Tipped Carbon Nanotubes," J. Phys. Chem., vol. 114 (18), pp 8282–8286, 2010.
[35] K. E. Spea, "Diamond -Ceramic Coating of the Future," J. Amer. Cer. Soc.72[2] 171-191(1989), p. 171, 1989.
[36] J. Walker, "Optical absorption and luminescence in diamond," Rep. Prog. Phys, vol. 42, 1979.
[37] T. P. Humphreys, et al., "The role of atomic hydrogen and its influence on the enhancement of secondary electron emission from C(001) surfaces," Applied Physics Letters, vol. 70, pp. 1257-1259, Mar 1997.
[38] M. L. Cohen, "Quantum Photoyield of Diamond (111) - A Stable Negative-Affinity Emitter -Comment," Physical Review B, vol. 22, pp. 1095-1095, 1980.
[39] I. L. Krainsky and V. M. Asnin, "Negative electron affinity mechanism for diamond surfaces," Applied Physics Letters, vol. 72, pp. 2574-2576, May 1998.
[40] J. Robertson and M. J. Rutter, "Band diagram of diamond and diamond-like carbon surfaces," Diamond and Related Materials, vol. 7, pp. 620-625, 1998.
[41] W. P. Kang, et al., "Subvolt turn-on voltage self-align gate diamond emitter fabricated by self-align-gate-sharpened molding technique," Journal of Vacuum Science & Technology B, vol. 17, pp. 740-743, Mar-Apr 1999.
[42] W. P. Kang, et al., "Micropatterned polycrystalline diamond field emitter vacuum diode arrays," Journal of Vacuum Science & Technology B, vol. 14, pp. 2068-2071, May-Jun 1996.
[43] E. S. Baik, et al., "Fabrication and emission properties of diode- and triode-type diamond field emitter array based on the transfer mold technique," Diamond and Related Materials, vol. 8, pp. 89-93, 1999.
[44] H. Shiomi, "Reactive Ion Etching of Diamond in O2 and CF4 Plasma, and Fabrication of Porous Diamond for Field Emitter Cathodes," Jpn. J. Appl. Phys, vol. 36, pp. 7745-7748 1997.
[45] H. Masuda, et al., "Synthesis of Well-Aligned Diamond Nanocylinders," Advanced Materials, vol. 13, pp. 247-249, 2001.
[46] A. Wisitsora-at, et al., "High current diamond field emission diode," J. Vac. Sci. Technol. B, Vol. 21, No. 4, 2003.
[47] W. J. Zhang, et al., "Structuring nanodiamond cone arrays for improved field emission," Applied Physics Letters, vol. 83, pp. 3365-3367, Oct 2003.
[48] Y. K. Chih, et al., "Formation of nano-scale tubular structure of single crystal diamond," Diamond and Related Materials, vol. 13, pp. 1614-1617, 2004.
[49] Y. K. Chih, et al., "The growth of nano-scale diamond tips on diamond/Si," Journal of Crystal Growth, vol. 283, pp. 367-372, 2005.
[50] J. Wang and T. Ito, "Improved field emission characteristics of nano-structured carbon films deposited on polycrystalline CVD diamond," Diamond and Related Materials, vol. 16, pp. 364-368, 2007.
[51] C. MY, et al., "Field emission from diamond nanotips treated with nitrogen plasma immersion ion implantation," Nanotechnology, vol. 18, p. 455706 (5pp), 2007.
[52] T. Yamada, et al., "Field emission properties of nano-structured phosphorus-doped diamond," Applied Surface Science, vol. 256, pp. 1006-1009, 2009.
[53] N. Shang, et al., "Self-Assembled Growth, Microstructure,and Field-Emission High-Performance of Ultrathin Diamond Nanorods," ACS Nano, vol. 3, p. 1032, 2009.
[54] R. N. Tiwari and L. Chang, "Growth, microstructure, and field-emission properties of synthesized diamond film on adamantane-coated silicon substrate by microwave plasma chemical vapor deposition," J. Appl. Phys, vol. 107, p. 103305, 2010.
[55] Hsiu-Fung Cheng, et al., "Enhanced electron field emission properties by tuning the microstructure of ultrananocrystalline diamond film," Journal of Applied Physics, vol. 109, p. 033711, 2011.
[56] Ken Okano, et al., "Low-threshold cold cathodes made of nitrogen-doped chemical-vapour-deposited diamond," Nature materials, vol. 381, p. 140, 1996.
[57] E. S. Baik, et al., "Control of diamond micro-tip geometry for field emitter," Thin Solid Films, vol. 377-378, pp. 299-302, 2000.
[58] Z. L. Wang, et al., "The high aspect ratio conical diamond tips arrays and their field emission properties," Diamond and Related Materials, vol. 15, pp. 631-634,2005.
[59] Q. Wang, et al., "Maskless Plasma Etching of Diamond Cones: The Role of CH4 Gas and Enhanced Field Emission Property," J. Phys. Chem. C vol. 111, pp. 7058-7062, 2007.
[60] W. Zhu, et al., "Low-Field Electron Emission from Undoped Nanostructured Diamond," Science, vol. 282, p. 20, 1998.
[61] D. Varshney, et al., "Growth and field emission study of a monolithic carbon nanotube/diamond composite," Carbon, vol. 48, pp. 3353-3358, 2010.
[62] H. M. a. K. Fukuda, "Ordered Metal Nanohole Arrays Made by a Two-Step Replication of Honeycomb Structures of Anodic Alumina," Science, vol. 268, p. 1466, 1995.
[63] L. X. •, et al., "Growth and field emission properties of nanotip arrays of amorphous carbon with embedded hexagonal diamond nanoparticles," Appl Phys A, vol. 103, p. 59, 2011.
[64] A. K. Geim and K. S. Novoselov, "The rise of graphene," Nature materials, vol. 6, pp. 183-190, 2007.
[65] Changgu Lee, et al., "Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene " Science, vol. 321, p. 385, 2008.
[66] 洪偉修, "世界上最薄的材料," 康熹化學報報, 2009年11月.
[67] "Graphene," wikipedia, 2011.
[68] http://nobelprize.org/nobel_prizes/physics/laureates/2010/.
[69] K. S. Novoselov, et al., "Electric Field Effect in Atomically Thin Carbon Films " Science, vol. 306, p. 666, 2004.
[70] G. Eda, et al., "Field emission from graphene based composite thin films," Applied Physics Letters, vol. 93, Dec 2008.
[71] Williams.HummersJR and R. OffenMan, "Preparation of Graphitic Oxide," J. Am. Chem. Soc, vol. 80, p. 1339, 1958.
[72] J. L. Liu, et al., "Improved field emission property of graphene paper by plasma treatment," Applied Physics Letters, vol. 97, Jul 2010.
[73] B. G. Streetman, Solid State Electronic Devices, vol. Fourth Edition , Prentice Hall International, 1995.
[74] 汪建民, "材料分析," 中國材料科學學會, 2005.
[75] 陳力俊, "材料電子顯微鏡學," 國家實驗研究院儀器科技研究中心, 1994.
[76] www.wikipedia.com, "ESCA."
[77] A. Grill, "Cold plasma in materials technology; from fundamentals to applications " IEEE Computer Society Press 1994.
[78] Paisan Kittisupakorn, et al., "Dynamic Neural Network Modeling for Hydrochloric Acid Recovery Process," Korean J. Chem. Eng., 22(6), 813-821, 2005.
[79] R.H. Fowler and L. Nordheim, "Electron Emission in Intense Elextric Fields," Proc. Roy. Soc. Lond., vol. A119, 173, 1928.
[80] A. Wisitsorat-at, "Micropatterned Diamond Vacuum Field Emission Devices," p. 10, 2002.
[81] M. W. Geis, et al., "Comparison of electric field emission from nitrogen-doped, type Ib diamond, and boron-doped diamond," Appl. Phys. Lett. 68 (16), 1996.
[82] e. a. TAkatoshi Yamada, "Field Emission Properties of Boron and Phoshporus Doped Diamond," New Diamond and Frontier Carbon Technology, vol. 15, p. No.6, 2005.
[83] M. Nagao, et al., "Influence of surface treatment and dopant concentration on field emission characteristics of boron-doped diamond thin films," Applied Physics Letters, vol. 71, pp. 2806-2808, Nov 1997.
[84] W. Zhu, et al., "Defect-enhanced electron field emission from chemical vapor deposited diamond," J. Appl. Phys, vol. 78, p. 2707, 1995.
[85] Michael Robert Jennings, et al., Electronic Materials Conference 2011.
[86] L. Nilsson, et al., "Scanning field emission from patterned carbon nanotube films," Applied Physics Letters, vol. 76, p. 2072, 2000.
[87] E. R. Batista and R. A. Friesner, "A Self-Consistent Charge-Embedding Methodology for ab Initio Quantum Chemical Cluster Modeling of Ionic Solids and Surfaces: Application to the (001) Surface of Hematite(r-Fe2O3)," J. Phys. Chem. B, vol. 106, p. 8136, 2002.
[88] J.-Y. Luo, et al., "The influence of film-to-substrate characteristics on the electron field emission behavior of the diamond films," Diamond and Related Materials, vol. 7, pp. 704-710, 1998.