臺灣博碩士論文加值系統

由於盤狀液晶分子具有自組裝排列的行為，其中共軛系統間π-π 作用力會形成柱狀結構時，有利於電荷傳遞而形成良好的載子通道。因此在兩電極間控制盤狀液晶其分子排列與堆疊方向將是決定電晶體元件效能的重要因素之一。 本實驗第一部分將討論數種盤狀液晶分子在基板表面形成薄膜後，其中分子排列情形。利用反射式紅外線光譜、粉末繞射光譜儀與偏光顯微鏡等工具鑑定分子排列情形。
另外有機電晶體元件中為了達到較高的工作電流，宜縮短通道間距離。而使用垂直式電晶體，可輕易縮短通道距離。故我們利用具有規則奈米柱陣列之結構製作垂直式電晶體進行實驗。第二部分實驗將以上所提到的數種盤狀液晶分子分別設法製成薄膜電晶體與垂直式電晶體進行比較，觀察盤狀液晶分子於奈米柱陣列中之分子排列方向。結果顯示於具有奈米柱基板上，分子的成膜性較好，並且排列明顯受到奈米柱影響。而在平坦基板上，分子受到分子間作用力影響，容易各自聚集成不連續塊狀，薄膜粗糙度高，無法鍍上電極。在製作橫向式薄膜電晶體中，只有盤狀液晶分子TC4TBC薄膜有測量到電性，約為7.59E-4 cm2V-1s-1。而在垂直式電晶體中盤狀液晶HAT7、HDBP、TC4TBC及HBC-F2OC16皆可以測量到場效特性。

The discotic liquid-crystals (DLCs) systems are appealing in organic electronics because of their solution-processibility and controllable inter-molecular ordering. Generally, these orderings are induced by the strong inter-planar π-π interactions and result in columnar self-assembly with hexagonal arrangement. These systems are expected to gives rise to better semiconducting properties with the charges hopping along stacks of π-conjugated planes. Therefore, to control the orientation of the column stakes between two electrodes would be an important issue in designing semiconducting devices, such as field-effect transistors. In the first part of this study, the orientations and structures of several discotic liquid crystals on surface were characterized using reflection-absorption infrared spectroscopy (RAIRS), powder X-ray diffractometer, polarizing microscope (POM) and atomic force microscope (AFM) to investigate the film structure. In the second part, in order to understand the semiconducting properties and packing behaviors of DLCs in different environments, the film structure on planar substrate and nanopillar-templated substrate were examined. Less morphological imperfections were observed when DLC films were formed on nanopillar-templated surfaces, compared to that on a planar surface. The sidewalls of nanopillars appear to assist the growth of DLCs into columnar alignment with their long-axis parallel to the nanopillar and against the substrate. FET devices are also fabricated for these materials. The mobility was measured in TC4TBC based lateral transistor devices and reached 7.59E-4 cm2V-1s-1. Field effect mobilities were measured for all four materials in vertical transistor configuration.

摘要
目錄
圖表目錄
壹 、緒論
1-1液晶簡介
1-1-1 平行配向Edge-on alignment
1-1-2 垂直配向Face-on alignment
1-2自組裝單分子薄膜原理與製備SELF-ASSEMBLED MONOLAYER
1-2-1 硫醇分子吸附於金基材
1-3場效電晶體簡介
1-3-1有機場效電晶體
1-3-2有機場效電晶體運作原理
1-3-3有機半導體電荷傳遞
1-3-4 載子遷移率計算
1-3-5垂直式場效電晶體
貳、研究動機
参、實驗步驟
3-1實驗藥品
3-1-1基材來源
3-1-2基板清洗
3-1-3有機薄膜製備藥品
3-2實驗儀器
3-2-1反射式傅立葉紅外線光譜儀
3-2-2橢圓膜厚儀Ellipsometry
3-2-3偏光顯微鏡 Polarizing microscope
3-2-4 X光粉末繞射儀X-ray powder diffractometer
3-2-5原子力顯微鏡 Atomic Force Microscopy
3-2-6掃描式電子顯微鏡 Scanning Electron Microscopy
3-2-7真空蒸鍍機 Vacuum Evaporator
3-2-8參數分析儀 Semiconductor Parameter Analyzer
3-3實驗步驟
3-3-1清洗矽晶片
3-3-2金屬蒸鍍
3-3-3硫醇自組裝單分子薄膜製備
3-3-4盤狀液晶薄膜製備
3-3-5上蓋模具製備
3-3-6盤狀液晶薄膜熱處理
3-3-7薄膜電晶體元件製備
3-3-8垂直電晶體元件製備
肆、結果與討論
4-1盤狀液晶在金基板表面的配向
4-1-1盤狀液晶HAT7於金基板上的表面分析
4-1-2盤狀液晶HAT7於矽晶片上的表面分析
4-1-3盤狀液晶HDBP於烷基硫醇修飾金上的表面分析
4-1-4盤狀液晶HDBP於矽晶片上的表面分析
4-1-5盤狀液晶TC4TBC於烷基硫醇修飾金上的表面分析
4-1-6盤狀液晶TC4TBC於矽晶片上的表面分析
4-1-7盤狀液晶HBC-F2OC16於烷基硫醇修飾金上的表面分析
4-1-8盤狀液晶HBC-F2OC16於矽晶片上的表面分析
4-2有機場效電晶體元件探討
4-2-1盤狀液晶HAT7應用於有機場效電晶體元件
4-2-2盤狀液晶HDBP應用於有機場效電晶體元件
4-2-3盤狀液晶TC4TBC應用於有機場效電晶體元件
4-2-4盤狀液晶HBC-F2OC16於有機場效電晶體
伍、結論
參考文獻

1. Chandrasekhar, S.; Suresh, K. A. Liquid crystals of disc-like molecules. Pramnna 1977, 9, 471-480.
2. Shklyarevskiy, I. O.; Jonkheijm, P.; Stutzmann, N.; Wasserberg, D.; Wondergem, H. J.; Christianen, P. C. M.; Schenning, A. P. H. J.; de Leeuw, D. M.; Tomović, Ž.; Wu, J.; Mullen, K.; Maan, J. C. High Anisotropy of the Field-Effect Transistor Mobility in Magnetically Aligned Discotic Liquid-Crystalline Semiconductors. Journal of the American Chemical Society 2005, 127, 16233-16237.
3. Van de craats, A. M.; Stutzmann, N.; Bunk, O.; Nielsen, M. M.; Watson, M.; Mullen, K.; Chanzy, H. D.; Sirringhaus, H.; Friend, R. H. Meso-Epitaxial Solution-Growth of Self-Organizing Discotic Liquid-Crystalline Semiconductors. Advanced Materials 2003, 15, 495-499.
4. Schmidt-Mende, L.; Fechtenkotter, A.; Mullen, K.; Moons, E.; Friend, R. H.; MacKenzie, J. D. Self-organized discotic liquid crystals for high-efficiency organic photovoltaics. Science 2001, 293, 1119-22.
5. Seguy, I.; Destruel, P.; Bock, H. An all-columnar bilayer light-emitting diode. Synthetic Metals 2000, 111-112, 15–18.
6. Laschat, S.; Baro, A.; Steinke, N.; Giesselmann, F.; Hagele, C.; Scalia, G.; Judele, R.; Kapatsina, E.; Sauer, S.; Schreivogel, A.; Tosoni, M. Discotic Liquid Crystals: From Tailor-Made Synthesis to Plastic Electronics. Angewandte Chemie International Edition 2007, 46, 4832-4887.
7. Kaafarani, B. R. Discotic Liquid Crystals for Opto-Electronic Applications. Chemistry of Materials 2011, 23, 378-396.
8. craats, A. M. v. d.; stutzmann, N.; Bunk, O.; Nielsen, M. M.; Watson, M.; Mullen, K.; Chanzy, H. D.; Sirringhaus, H.; Friend, R. H. Meso-Epitaxial Solution-Growth of Self-Organizing Discotic Liquid-Crystalline Semiconductors. Advanced Materials 2003, 15, 499-495.
9. Bunk, O.; Nielsen, M. M.; Solling, T. I.; Craats, A. M. v. d.; Stutzmann, N. Induced Alignment of a Solution-Cast Discotic Hexabenzocoronene Derivative for Electronic Devices Investigated by Surface X-ray Diffraction. Journal of the American Chemical Society 2003, 125, 2252-2258.
10. Pisula, W.; Menon, A.; Stepputat, M.; Lieberwirth, I.; Kolb, U.; Tracz, A.; Sirringhaus, H.; Pakula, T.; Mullen, K. A Zone-Casting Technique for Device Fabrication of Field-Effect Transistors Based on Discotic Hexa-peri-hexabenzocoronene. Advanced Materials 2005, 17, 684-689.
11. Tracz, A.; Jeszka, J. K.; Watson, M. D.; Pisula, W.; Mullen, K.; Pakula, T. Uniaxial
78
Alignment of the Columnar Super-Structure of a Hexa (Alkyl) Hexa-peri-hexabenzocoronene on Untreated Glass by Simple Solution
Processing. Journal of the American Chemical Society 2003, 125, 1682-1683.
12. Monobe, H.; Awazu, K.; Shimizu, Y. Change of Liquid-Crystal Domains by Vibrational Excitation for a Columnar Mesophase. Advanced Materials 2000, 12, 1495-1499.
13. Kumaran, N.; Veneman, P. A.; Minch, B. A.; Mudalige, A.; Pemberton, J. E.; O’Brien, D. F.; Armstrong, N. R. Self-Organized Thin Films of Hydrogen-Bonded Phthalocyanines: Characterization of Structure and Electrical Properties on Nanometer Length Scales. Chemistry of Materials 2010, 22, 2491-2501.
14. Lee, S.-L.; Lin, H.-A.; Lin, Y.-H.; Chen, H.-H.; Liao, C.-T.; Lin, T.-L.; Chu, Y.-C.; Hsu, H.-F.; Chen, C.-h.; Lee, J.-J.; Hung, W.-Y.; Liu, Q.-Y.; Wu, C. Gearing of Molecular Swirls: Columnar Packing of Nematogenic Hexakis(4-alkoxyphenylethynyl)benzene Derivatives. Chemistry – A European Journal 2011, 17, 792-799.
15. Cour, I.; Pan, Z.; Lebruin, L. T.; Case, M. A.; Furis, M.; Headrick, R. L. Selective orientation of discotic films by interface nucleation. Organic Electronics 2012, 13, 419-424.
16. Brzoska, J. B.; Azouz, I. B.; Rondelez, F. Silanization of Solid Substrates: A Step Toward Reproducibility. Langmuir 1994, 10, 4367-4373.
17. Delamarche, E.; Michel, B.; Kang, H.; Gerber, C. Thermal Stability of Self-Assembled Monolayers. Langmuir 1994, 10, 4103-4108.
18. Allara, D. L.; Nuzzo, R. G. Spontaneously organized molecular assemblies. 2. Quantitative infrared spectroscopic determination of equilibrium structures of solution-adsorbed n-alkanoic acids on an oxidized aluminum surface. Langmuir 1985, 1, 52-66.
19. Labins, P. E.; Hickman, J. J.; Wrighton, M. S.; Whiteside, G. M. Orthogonal Self-Assembled Monolayers: Alkanethiols on Gold and Alkane Carboxylic Acids on Alumina. Science 1989, 245, 845-847.
20. Tao, Y. T.; Lee, M. T.; Chang, S. C. Effect of biphenyl and naphthyl groups on the structure of self-assembled monolayers: packing, orientation, and wetting properties. Journal of the American Chemical Society 1993, 115, 9547-9555.
21. Yu, S.-Y.; Huang, D.-C.; Chen, Y.-L.; Wu, K.-Y.; Tao, Y.-T. Approaching Charge Balance in Organic Light-Emitting Diodes by Tuning Charge Injection Barriers with Mixed Monolayers. Langmuir 2011, 28, 424-430.
22. Laibinis, P. E.; Whitesides, G. M.; Allara, D. L.; Tao, Y. T.; Parikh, A. N.; Nuzzo, R. G. Comparison of the structures and wetting properties of self-assembled monolayers of n-alkanethiols on the coinage metal surfaces, copper, silver, and gold. Journal of the American Chemical Society 1991, 113, 7152-7167.
79
23. Ulamn, A. An Introduction to Ultrathin Organic Films:From Langmuir-Blodgett to Self-assembly. Academic Press: Boston 1991.
24. Widrig, C. A.; Alves, C. A.; Porter, M. D. Scanning tunneling microscopy of ethanethiolate and n-octadecanethiolate monolayers spontaneously absorbed at gold surfaces. Journal of the American Chemical Society 1991, 113, 2805-2810.
25. Tsumura, A.; Koezuka, H.; Ando, T. Macromolecular electronic device: Field-effect transistor with a polythiophene thin film. Applied Physics Letters 1986, 49, 1210.
26. Kelley, T. W.; Baude, P. F.; Gerlach, C.; Ender, D. E.; Muyres, D.; Haase, M. A.; Vogel, D. E.; Theiss, S. D. Recent Progress in Organic Electronics: Materials, Devices, and Processes. Chemistry of Materials 2004, 16, 4413-4422.
27. Joughin, I. Tributaries of West Antarctic Ice Streams Revealed by RADARSAT Interferometry. Science 1999, 286 , 283-286.
28. Haddock, J. N.; Zhang, X.; Zheng, S.; Zhang, Q.; Marder, S. R.; Kippelen, B. A comprehensive study of short channel effects in organic field-effect transistors. Organic Electronics 2006, 7, 45-54.
29. Deibel, C.; Janssen, D.; Heremans, P.; De Cupere, V.; Geerts, Y.; Benkhedir, M. L.; Adriaenssens, G. J. Charge transport properties of a metal-free phthalocyanine discotic liquid crystal. Organic Electronics 2006, 7, 495-499.
30. Iino, H.; Takayashiki, Y.; Hanna, J.-i.; Bushby, R. J.; Haarer, D. High electron mobility of 0.1cm[sup 2]V[sup −1]s[sup −1] in the highly ordered columnar phase of hexahexylthiotriphenylene. Applied Physics Letters 2005, 87, 192105.
31. Zheng, W.; Hu, Y. T.; Chiang, C. Y.; Ong, C. W. Orientational packing of a confined discotic mesogen in the columnar phase. International Journal of Molecular Sciences 2010, 11, 943-55.
32. Neville Boden; Richard J. Bushby; Philip S. Martin; Stephen D. Evans; Robert W. Owens; Smith, D. A. Triphenylene-Based Discotic Liquid Crystals as Self-Assembled Monolayers. Langmuir 1999, 15.
33. Miyake, Y.; Fujii, A.; Ozaki, M.; Shimizu, Y. Carrier mobility of a columnar mesophase formed by a perfluoroalkylated triphenylene. Synthetic Metals 2009, 159, 875-879.
34. Xiaojie Zhang; Jiang, X.; Zhang, K.; Mao, L.; Jing Luo; Chi, C.; Chan, H. S. O.; Wu, J. Synthesis, self-assembly, and charge transporting property of contorted tetrabenzocoronenes. The Journal of Organic Chemistry 2010, 75, 8069-77.
35. Ito, S.; Wehmeier, M.; Brand, J. D.; Kubel, C.; Epsch, R.; Rabe, J. P.; Mullen, K. Synthesis and Self-Assembly of Functionalized Hexa-peri-hexbenzocoronenes. Chemistry - A European Journal 2000, 6, 4342-4327.
36. astler, M.; La uai, F. d. r.; M llen, K.; Wegner, G. Room-temperature
80
nondispersive hole transport in a discotic liquid crystal. Applied Physics Letters 2006, 89, 252103.
37. Anick M. van de Craats; Warman, J. M.; Fechtenkotter, A.; Brand, J. D.; Harbison, M. A.; Mullen, K. Record Charge Carrier Mobility in a Room-Temperature Discotic Liquid-Crystalline Derivative of Hexabenzocoronene. Advanced Materials 1999, 11, 1469-1472.
38. Warman, J. M.; Haas, M. P. d.; Dicker, G.; Grozema, F. C.; Piris, J.; Debije, M. G. Charge Mobilities in Organic Semiconducting Materials Determined by Pulse-Radiolysis Time-Resolved Microwave Conductivity: π-Bond-Conjugated Polymers versus π-π-Stacked Discotics. Chemistry of Materials 2004, 16, 4600-4609.