臺灣博碩士論文加值系統

傳統的表面傳導電子發射射極由具有奈米狹縫之氧化鈀薄膜所組成。施加電壓於氧化鈀薄膜而產生穿隧電子與散射電子。雖然奈米狹縫為表面傳導電子發射射極很重要的一環，但奈米狹縫不易製造，且加工複雜。所以為了簡化製程及改善其電子發射效率，本論文提出以垂直成長奈米碳管陣列來取代氧化鈀薄膜作為新型之表面傳導電子發射射極。使用熱化學氣相沉積法在石英基板上合成奈米碳管陣列。本實驗利用尖端放電的原理，將具有20度尖角之三角星形碳管陣列設計作為放射陰極。為了增強奈米碳管陣列的電子放射特性，使用電子束蒸鍍法將氧化鎂奈米結構成長於奈米碳管表面。本論文研究披覆氧化鎂奈米結構之奈米碳管陣列的二次電子放射特性。實驗結果顯示，量測披覆氧化鎂奈米結構之奈米碳管陣列，可得放射電流為0.13 mA。其結果證實氧化鎂奈米結構披覆於奈米碳管陣列可以增強二次電子放射特性與改善電子發射效率，並可應用於表面傳導電子顯示器。

Traditional surface-conduction electron-emitters (SCEs) consist of the palladium oxide (PdO) film with a nanogap. The electrons can be emitted by applying a voltage to the PdO film and scattered on the PdO film. Although the nanogap is a crucial part of SCEs, the manufacture of a nanogap is quite difficult and complex. To simplify the process and improve the electron emission efficiency, the PdO film is replaced by the vertically aligned carbon nanotube (CNT) arrays. The CNT arrays were synthesized on the quartz substrates using a thermal chemical vapor deposition (CVD) system. In this study, the delta-star shaped CNT arrays with 20o tips as the cathodes emitted the electron easily due to the high electrical field gradient. To enhance the electron emission characteristics of the CNTs arrays, the magnesium oxide (MgO) nanostructures were coated on the CNT arrays using electron beam evaporation. The secondary electron emission characteristics of MgO-coated CNT arrays were investigated. The experimental results showed the emission current of 0.13 mA was obtained from the 10 nm-MgO-coated CNT arrays. The MgO nanostructure coated on the CNT arrays could improve the secondary electron emission characteristic. The SCEs based on the MgO-coated CNT arrays promise application in the surface-conduction electron-emitter displays in the near future.

Contents
Abstract (in Chinese) -------------------------------------------------------- I
Abstract (in English) --------------------------------------------------------- II
Acknowledgement (in Chinese) ------------------------------------------ III
Contents ----------------------------------------------------------------------- IV
Figure captions --------------------------------------------------------------- VI
Table list ------------------------------------------------------------------------ IX
Chapter 1 Introduction ------------------------------------------------------ 1
1.1 Introduction to displays ------------------------------------------------ 1
1.1.1 Types of display -------------------------------------------------------- 1
1.1.2 Surface-conduction electron-emitter display (SED) ----------- 2
1.2 Structure and properties of carbon nanotubes ------------------- 4
1.2.1 Categories of carbon nanotubes ----------------------------------- 4
1.2.2 Properties of carbon nanotubes ------------------------------------ 6
1.3 Field emission basics ----------------------------------------------------- 7
1.3.1 Theory of field emission ---------------------------------------------- 7
1.3.2 Electron source for field emission ---------------------------------- 8
1.4 Secondary electron basics ---------------------------------------------- 9
1.4.1 Coefficient of secondary electron emission yield -------------- 10
1.4.2 Escape depth of secondary electron ------------------------------ 10
1.5 Motivation ----------------------------------------------------------------- 11
1.5.1 Geometrical structure of carbon nanotube arrays ------------- 11
1.5.2 Magnesium oxide-coated carbon nanotubes -------------------- 12
Chapter 2 Experimental methods ------------------------------------------ 13
2.1 Experimental procedure ------------------------------------------------- 13
2.2 Manufacturing procedure ----------------------------------------------- 14
2.2.1 Substrate preparation -------------------------------------------------- 14
2.2.2 Photolithography -------------------------------------------------------- 14
2.2.3 E-beam evaporation ---------------------------------------------------- 16
2.2.4 The growth of carbon nanotubes ------------------------------------ 17
2.2.5 The synthesis of MgO-coated CNTs ---------------------------------- 19
2.3 Analysis and characterization -------------------------------------------- 21
2.3.1 Scanning electron microscopy (SEM) -------------------------------- 21
2.3.2 High resolution transmission electron microscopy (HRTEM)--- 22
2.3.3 X-ray photoelectron spectroscopy (XPS) ---------------------------- 22
2.3.4 X-ray diffraction (XRD) --------------------------------------------------- 22
2.3.5 Secondary electron emission measurement system ------------- 23
Chapter 3 Results and discussion -------------------------------------------- 26
3.1 Pristine CNT arrays -------------------------------------------------------- 26
3.2 MgO-coated CNT arrays -------------------------------------------------- 31
Chapter 4 Conclusions --------------------------------------------------------- 44
References ------------------------------------------------------------------------ 46
Resume ---------------------------------------------------------------------------- 52
Publication list ------------------------------------------------------------------- 53

References

[1]Y. S. Choi, “Shapes of emitter surface in field emission display,” Thin Solid Films, vol. 516, pp. 3357-3363, 2008.
[2]J.-L. Kwo, M. Yokoyama, and I.-N. Lin, “Effects of composition on field emission character of tetrahedral amorphous carbon,” Appl. Surf. Sci., vol. 142, pp. 521-526, 1999.
[3]H. Takiguchi, “Technology-development trend of liquid crystal display,” Shapu Giho/Sharp Technical J., vol. 74, pp. 5-11, 1999.
[4]T. Oguchi, E. Yamaguchi, K. Sasaki, K. Suzuki, and S. Uzawa, “A 36-inch surface-conduction electron-emitter display (SED),” J. SID., vol. 36, pp. 1929-1931, 2005.
[5]K. Yamamoto, I. Nomura, K. Yamazaki, and S. Uzawa, “Fabrication and characterization of surface conduction electron emitters,” J. SID., vol. 36, pp. 1933-1935, 2005.
[6]S. Reich, C. Thomsen, and J. Maultzsch, “Carbon nanotubes: basic concepts and physical properties,” Germany: Wiley-VCH, 2004.
[7]S. Iijima, “Helical microtubules of graphitic carbon,” Nature, vol. 354, pp. 56-58, 1991.
[8]S. Iijima and T. Ichihashi, “Single-shell carbon nanotubes of 1-nm diameter,” Nature, vol. 363, pp. 603-605, 1993.
[9]D. S. Bethune, C. H. Klang, M. S. de Vries, G. Gorman, R. Savoy, J. Vazquez, and R. Beyers, “Cobalt-catalysed growth of carbon nanotubes with single-atomic-layer walls,” Nature, vol. 363, pp. 605-607, 1993.
[10]A. Thess, R. Lee, P. Nikolaev, H. J. Dai, P. Petit, J. Robert, C. H. Xu, Y. H. Lee, S. G. Kim, A. G. Rinzler, D. T. Colbert, G. E. Scuseria, D. Tomanek, J. E. Fischer, and R. E. Smalley, “Crystalline ropes of metallic carbon nanotubes,” Science, vol. 273, pp. 483-487, 1996.
[11]G. S. Choi, K. H. Son, and D. J. Kim, “Fabrication of high performance carbon nanotube field emitters,” Microelectron. Eng., vol. 66, pp. 206-212, 2003.
[12]P. R. Somani, S. P. Somani, S.P. Lau, E. Flahaut, M. Tanemura, and M. Umeno, “Field electron emission of double walled carbon nanotube film prepared by drop casting method,” Solid State Electron., vol. 51, pp. 788-792, 2007.
[13]Y. Qin, M. Hu, H. Li, Z. Zhang, and Q. Zou, “Preparation and field emission properties of carbon nanotubes cold cathode using melting Ag nano-particles as binder,” Appl. Surf. Sci., vol. 253, pp. 4021-4024, 2008.
[14]J. W. Mintmire and C. T. White, “Electronic and structural properties of carbon nanotubes,” Carbon, vol. 33, pp. 893-902, 1995.
[15]W. I. Milne, K. B. K. Teo, G. A. J. Amaratunga, P. Legagneux, L. Gangloff, J.-P. Schnell, V. Semet, V. Thien Binh, and O. Groening, “Carbon nanotubes as field emission sources,” J. Mater. Chem., vol. 14, pp. 933 – 943, 2004.
[16]A. G. Rinzler, J. H. Hafner, P. Nikolaev, P. Nordlander, D. T. Colbert, R. E. Smalley, L. Lou, S. G. Kim, and D. Tománek, “Unraveling nanotubes: Field emission from an atomic wire,” Science, vol. 269, no. 5230, pp. 1550-1553, 1995.
[17]S. Fan, M. G. Chapline, N. R. Franklin, T. W. Tombler, and A. M. Cassell, “Self-oriented regular arrays of carbon nanotubes and their field emission properties,” Science, vol. 283, no. 5401, pp. 512-514, 1999.
[18]H. Huang, C. H. Liu, Y. Wu, and S. Fan, “Aligned carbon nanotube composite films for thermal management,” Adv. Mater., vol. 17, pp. 1652-1656, 2005.
[19]G. Fursey, I. Brodie, and P. Shwoebel, “Field emission in vacuum microelectronics,” US: Kluwer Academic Pub, 2005.
[20]R. H. Fowler and L. W. Nordheim, “Electron emission in intense electric fields,” Proc. R. Soc. London A, vol. 119, pp. 173-181, 1928.
[21]C.A. Spindt, “A thin‐film field‐emission cathode,” J. Appl. Phys., vol. 39, pp. 3504-3505, 1968.
[22]S. Albin, W. Fu, A. Varghese, and A.C. Lavarias, “Diamond coated silicon field emitter array,” J. Vac. Sci. Technol. A, vol. 17, pp. 2104-2108, 1999.
[23]N. S. Xu and R. V. Latham, “Similarities in the cold electron emission characteristics of diamond coated molybdenum electrodes and polished bulk graphite surfaces,” J. Phys. D, vol. 26, pp. 1776-1780, 1993.
[24]M. Q. Ding, D. M. Gruen, A. R. Krauss, O. Auciello, T. D. Corrgan, and R. P. H. Chang, “Studies of field emission from bias-grown diamond thin films,” J. Vac. Sci. Technol. B, vol.17, pp. 705-709, 1999.
[25]S. H. Jo, J. Y. Lao, Z. F. Ren, R. A. Farrer, T. Baldacchini, and J. T. Fourkas, “Field-emission studies on thin films of zinc oxide nanowires,” Appl. Phys. Lett., vol. 83, pp. 4821-4823, 2003.
[26]K. A. Dean, P. von Allmen, and B. R. Chalamala, “Three behavioral states observed in field emission from single-walled carbon nanotubes,” J. Vac. Sci. Technol. B, vol. 17, pp. 1959-1969, 1999.
[27]H. Gao, C. Mu, F. Wang, D. Xu, K. Wu, Y. Xie, S. Liu, E. Wang, J. Xu, and D. Yu, “Field emission of large-area and graphitized carbon nanotube array on anodic aluminum oxide template,” J. Appl. Phys., vol. 93, pp. 5602-5605, 2003.
[28]B. Q. Zeng, G. Y. Xiong, S. Chen, W. Z. Wang, D. Z. Wang, and Z. F. Ren, “Enhancement of field emission of aligned carbon nanotubes by thermal oxidation,” Appl. Phys. Lett., vol. 89, pp. 223119, 2006.
[29]F. Lu, W. P. Cai, Y. G. Zhang, Y. Li, and F. Sun, “Fabrication and field-emission performance of zinc sulfide nanobelt arrays,” J. Phys. Chem. C, vol. 111, pp. 13385-13392, 2007.
[30]J. Chen, S. Z. Deng, N. S. Xu, W. X. Zhang, X. G. Wen, and S. H. Yang, “Temperature dependence of field emission from cupric oxide nanobelt films,” Appl. Phys. Lett., vol. 83, pp. 746-748, 2003.
[31]Y. B. Li, Y. Bando, D. Golberg, and K. Kurashima, “Field emission from MoO3 nanobelts,” Appl. Phys. Lett., vol.81, pp. 5048-5050, 2002.
[32]C. J. Lee, T. J. Lee, S. C. Lyu, Y. Zhang, H. Ruh, and H. J. Lee, “Field emission from well-aligned zinc oxide nanowires grown at low temperature,” Appl. Phys. Lett., vol. 81, pp. 3648-3650, 2002.
[33]J. Zhou, N. S. Xu, S. Z. Deng, J. Chen, J. C. She, and Z. L. Zhong, “Large-area nanowire arrays of molybdenum and molybdenum oxides: synthesis and field emission properties,” Adv. Mater., vol. 15, pp. 1835-1840, 2003.
[34]J. Zhou, N. S. Xu, S. Z. Deng, J. Chen, and J. C. She, “Synthesis of large-scaled MoO2 nanowire arrays,” Chem. Phys. Lett., vol. 382, pp. 443-446, 2003.
[35]J. Zhou, S. Z. Deng, N. S. Xu, J. Chen, and J. C. She, “Synthesis and field-emission properties of aligned MoO3 nanowires,” Appl. Phys. Lett., vol. 83, pp. 2653-2655, 2003.
[36]H. Seiler, “Secondary electron emission in the scanning electron microscope,” J. Appl. Phys., vol. 54, pp. R1-R18, 1983.
[37]J. J. Scholtz, D. Dijkkamp, and R. W. A. Schmitz, “Secondary electron emission properties,” Philips J. Res., vol. 50, pp. 374-389, 1996.
[38]J. Pillon, D. Roptin, and M. Cailler, “Secondary electron emission from aluminum,” Surf. Sci., vol. 59, pp. 741-748, 1976.
[39]K. Kanaya, S. Ono, and F. Ishigaki. “Secondary electron emission from insulators,” J. Phys. D, vol. 11, pp. 2425-2437, 1978.
[40]W. K. Yi, T. W. Jeong, S. G. Yu, J. N. Heo, C. S. Lee, J. H. Lee, W. S. Kim, J.-B. Yoo, and J. M. Kim, “Field-emission characteristics from wide-bandgap material-coated carbon nanotubes,” Adv. Mater., vol. 14, pp. 1464-1468, 2002.
[41]W. Yi, S. Yu, W. Lee, I. T. Han, T. Jeong, Y. Woo, J. Lee, S. Jin, W. Choi, J. Heo, D. Jeon, and J. M. Kim, “Secondary electron emission yields from MgO deposited on carbon nanotubes,” J. Appl. Phys., vol. 89, pp. 4091-4095, 2001.
[42]J. N. Heo, W. S. Kim, T. W. Jeong, S. Yu, J. H. Lee, C. S. Lee, W. K. Yi, Y. H. Lee, J. B. Yoo, and J. M. Kim, “Effect of MgO film thickness on secondary electron emission from MgO-coated carbon nanotubes,” Phys. B, vol. 323, pp. 174-176, 2002.
[43]W. S. Kim, W. Yi, S. Yu, J. Heo, T. Jeong, J. Lee, C. S. Lee, J. M. Kim, H. J. Jeong, Y. M. Shin, and Y. H. Lee, “Secondary electron emission from magnesium oxide on multiwalled carbon nanotubes,” Appl. Phys. Lett., vol. 81, pp. 1098-1100, 2002.
[44]J. Lee, J. Park, J. Kim, and W. Yi, “Effect of double layer coating on carbon nanotubes for field emission and secondary electron emission measurement,” J. Vac. Sci. Technol. B, vol. 25, pp. 570-574, 2007.
[45]Z.-N. Yu, J.-W. Seo, D.-X. Zheng, and J. Sun, “Structural and discharging properties of MgO thin films prepared by ion beam-assisted deposition,” Surf. Coat. Technol., vol. 163-164, pp. 398-404, 2003.
[46]Y. Yan, L. Zhou, and Y. Zhang, “Synthesis of MgO hierarchical nanostructures controlled by the supersaturation ratio,” J. Phys. Chem. C, vol. 112, pp. 19831-19835, 2008.
[47]T. V. Sreekumar, T. Liu, and S. Kumar, ” Single-wall carbon nanotube films,” Chem. Mater., vol. 15, pp. 175-178, 2003.
[48]D. K. Aswal, K. P. Muthe, S. Tawde, S. Chodhury, N. Bagkar, A. Singh, S. K. Gupta, and J. V. Yakhimi, “XPS and AFM investigations of annealing induced surface modifications of MgO single crystals,” J. Cryst. Growth, vol. 236, pp. 661-666, 2002.
[49]H. B. Yao, Y. Li, and A. T. S. Wee, “An XPS investigation of the oxidationrcorrosion of melt-spun Mg,” Appl. Surf. Sci., vol. 158, pp. 112-119, 2000.
[50]D. Caceres, I. Colera, I. Vergara, R. Gonzalez, and E. Roman, “Characterization of MgO thin films grown by rf-sputtering,” Vacuum, vol. 67, pp. 577-581, 2002.
[51]P. Casey, E. OConnor, R. Long, B. Brennan, S.A. Krasnikov, D. OConnell, P. K. Hurley, and G. Hughes, “Growth, ambient stability and electrical characterisation of MgO thin films on silicon surfaces,” Microelectron. Eng., vol. 86, pp. 1711-1714, 2009.
[52]C. Xu and D. W. Goodman, “Structure and geometry of water adsorbed on the MgO(100) surface,” Chem. Phys. Lett., vol. 265, pp. 341-346, 1997.
[53]S. H. Moon, T. W. Heo, S. Y. Park, J. H. Kim, and H. J. Kim, “The effect of the dehydration of MgO films on their XPS spectra and electrical properties,” J. Electrochem. Soc., vol. 154, pp. J408-J412, 2007.
[54]J. Lee, T. Jeong, S. Yu, S. Jin, J. Heo, W. Yi, D. Jeon, and J. M. Kim, “Thickness effect on secondary electron emission of MgO layers,” Appl. Surf. Sci., vol. 174, pp.62-69, 2001.