臺灣博碩士論文加值系統

高分子有機半導體Regioregular Poly(3-hexythiophene)，簡稱RR-P3HT(高度立體規則度聚(3-己烷基噻吩))是目前常用的有機薄膜半導體材料。高分子有機半導體可利用旋轉塗佈或噴墨列印之方式形成薄膜，噴印製程比旋轉塗佈製程，在成膜時能讓高分子有機半導體有較長的時間排列分子，形成較好的結構，而獲得較佳之電特性表現，因此本實驗以RR-P3HT為基礎，研究以噴印的方式製作有機薄膜電晶體，並嘗試改善元件結構，以提升元件之工作效率。
提升有機高分子工作效能為實驗第一部份，改善高分子半導體與絕緣層接面之接觸狀況(morphology)，利用水性聚脲酯(Polyurethane, PU)作為半導體與絕緣層接面之修飾層 (modification layer)，PU提供P3HT分子成膜時較佳排列效果，進而改善元件電特性。本實驗嘗試多種厚度的PU參數，且在PU厚度3300 Å得到最佳化的元件性能。並改變半導體層P3HT濃度，以及不同寬長比之研究，由實驗結果發現P3HT溶液濃度之提高有效的改善元件電特性參數，而寬長比則沒有在特定參數會有顯著的變化。又研究在PU薄膜上以不同瓦數氧電漿進行處理，藉以改變表面的能量，實驗結果指出此方法可以用來控制元件的起始電壓。
實驗的第二部份以製作全噴墨製程的有機薄膜電晶體為目標，將元件的源極與汲極之Au/Al金屬電極改以PEDOT:PSS溶液來代替。由實驗結果發現使用PEDOT:PSS溶液當電極的元件電特性會不如使用Au/Al金屬當電極的元件。進一步探討原因，藉由四點探針、表面能及接觸電阻的實驗發現，因為其極性的差異、接觸及通道電阻過大，並且傳導率不佳，導致利用PEDOT:PSS溶液當電極的元件電特性會有所下降。

Inkjet-printed regioregular poly-(3-hexythiophene) (RR-P3HT) was used in this research to fabricate organic thin film transistors (OTFTs). The inkjet-printing method has an advantage of longer assembly time than spin-coating method for forming RR-P3HT films to achieve better performance of OTFTs. In the first section, the inkjet-printed P3HT-based OTFT with polyurethane (PU) as modification layer shows higher ordering P3HT film than that spinning directly on SiO2 gate-dielectric. The processing parameters, including the thickness of PU layer, the concentration of P3HT, and the channel length of OTFTs, had been optimized in this study. Interestingly, the threshold voltages of OTFT devices could be controlled by the surface energy of the PU films processed under various doses of O2-plasma. In the second part, an electrically conducting polymer blend poly(3,4-ethylenedioxythiophene) oxidized with poly(4-styrenesulfonate), PEDOT-PSS, was used to replace the metal electrodes in the OTFTs in order to form an all organic thin film transistor. However, a high contact resistance existed between the P3HT and PEDOT-PSS films. The extraction of the contact resistance using a gate-transfer length method preformed on a series of devices with channel length ranging from 400 to 800 μm and a fixed channel width of 2000 μm. Moreover, the surface polarities of P3HT and PEDOT-PSS could not match to each other; therefore, no all organic transistors can be achieved in this thesis.

中文摘要 I
Abstract III
誌謝 V
目錄 VII
表目錄 XI
圖目錄 XII
第1章 緒論 1
1.1 有機半導體(organic semiconductor) 1
1.2 水性光學塑膠材料 2
1.3 有機薄膜電晶體(Organic thin-film transistors, OTFTs) 3
1.3.1 元件結構 3
1.3.2 原理 4
1.3.3 描述有機薄膜電晶體電特性的基本公式 6
1.4 研究目的 8
第2章 P3HT有機薄膜電晶體元件設計 17
2.1 前言 17
2.2 實驗方法 17
2.2.1 有機材料 17
2.2.2 樣品設計 18
2.2.3 樣品製作 20
2.3 實驗儀器 20
第3章 探討介電層及半導體層對於有機薄膜電晶體元件的影響 37
3.1 前言 37
3.2 元件製作 37
3.3 電性分析 38
3.3.1 不同濃度絕緣層的影響 38
3.3.2 不同濃度主動層在不同通道比之下的影響 42
3.4 在修飾層上面以不同瓦數氧電漿處理對電性的影響 43
3.4.1 元件製作 44
3.4.2 電性分析 45
第4章 利用噴墨技術製作半導體元件 62
4.1 前言 62
4.2 元件製作 62
4.3 電性分析 63
4.4 不同的電極對於元件的影響 66
4.4.1 表面能 66
4.4.2 接觸電組與通道電阻[40-42] 68
第5章 結論與未來展望 83
5.1 結論 83
5.2 未來展望 85
參考文獻 86

[1]. J. Bardeen, W. H. Brattain, “The transistor, a semi-conductor triode” Physical Review 74, 230 (1948).
[2]. A. Szent-Györgyi, “Towards a new biochemistry”, Science 32, 609 (1941).
[3]. C. K. Chiang, C. R. Fincher, Y. W. Park, A. J. Heeger, H. Shirakawa, E. J. Louis, S. C. Gau, A. G. Macdiarmid, “Electrical conductivity in doped polyacetylene”, Physical Review Letters 39, 1098 (1977).
[4] Y. Sun, Y. Liu, D. Zhu, “Advances in organic field-effect transistors”, Journal of Materials Chemistry 15, 53 (2005).
[5] A. Tsumura, H. Koezuka, T. Ando, “Macromolecular electronic device: field-effect transistor with a polythiophene thin film”, Applied Physics Letters 49, 1210 (1986).
[6] J. H. Saunders, K. C. Frisch. “Polyurethane, Chemistry and technology”﹐Wiley Interscience﹐New York, p.1498 (1962).
[7] P. Wright, A. P. C. Cumming, “Solid polurethane elastomers”, Maclaren and Sons, London, (1969).
[8] J. W. Cho, S. H. Lee, “Influence of silica on shape memory effect and mechanical properties of polyurethane–silica hybrids” The European Polymer Journal 40, 1343 (2004).
[9] H. Biederman, D. Slavinska, “Plasma polymer film and their future prospects”, Surface and Coatings Technology 125, 371 (2000).
[10] W. Ehrfeld, “Electrochemistry and microsystems”, Electrochimica Acta 48, 2857 (2003).
[11] H. Sato, S. Nishio, “Polymer laser photovhemistry, ablation, reconstruction, and polymerization”, Journal of Photochemistry and Photobiology 2, 139 (2001).
[12] M. Jakoublova, Z. Bastl, R. Fajgar, J. Pola, “Laser induced chemicalvapour deposistion of polymeric films from thiophene”, Applied Surface Science 106, 67 (1996).
[13] R. V. Plank, Y. Wei, N. J. DiNardo, J. M. Vohs, “Characterization of highly conducting, ultra-thin polyaniline films produced by evaporative deposition”, Chemical Physics Letters 263, 33 (1996).
[14] J. Gonzalo, P. E. Dyer, M. Hird, “Pulsed laser deposition of liquid crystals”, Applied Physics Letters 71, 19 (1997).
[15] Y. Liu, T. Cui, K. Varahramyan, “Fabrication and characteristics of polymeric thin-film capacitor”, Soild-State Electronics 47, 811 (2003).
[16] H. Sirringhaus, T. Kawase, R. H. Friend, T. Shimoda, M. Inbasekaran, W. Wu, E. P. Woo, “High-resolution inkjet printing of all-polymer transistor circuits”, Science 290, 15 (2000).
[17] M. Leufgen, A. Lebib, T. Muck, U. Bass, V. Wagner, T. Borzenko, J. Geurts, L. W. Molenkamp, “Organic thin-film transistor fabricated by microcontact printing”, Applied Physics Letters 84, 1582 (2004)
[18] C. D. Dimitrakopoulos, P. R. L. Malenfant, “Organic thin film transistors for large area electronics”, Advanced Materials 14, 16 (2002).
[19] 孫允武, 中興物理系, 應用電子學講義.
[20] 施敏, “半導體元件物理與製造技術”, 高立出版社 , p.223 (1997).
[21] H. Yang, T. J. Shin, L. Yang, K. Cho, C. Y. Ryu, Z. Bao, “Effect of mesoscale crystalline structure on the field-effect mobility of regioregular poly(3-hexylthiophene) in thin-film transistors”, Advanced Functional Materials 15, 671 (2005).
[22] F. Xue, Y. Su, K. Varahramyan, “Modified PEDOT-PSS conducting polymer as S/D electrodes for device performance enhancement of P3HT TFTs”, IEEE Transactions on Electron Device 52, 1982 (2005).
[23] S. K. Park, Y. H. Kim, J. I. Han, D. G. Moon, W. K. Kim, “High-performance polymer TFTs printed on a plastic substrate”, IEEE Transactions on Electron Device 49, 2008 (2002).
[24] M. J. Deen, M. H. Kazemeini, Y. M. Haddara, J. Yu, G. Vamvounis, S. Holdcroft, W. Woods, “Electrical characterization of polymer- based FETs fabricated by spin-coating poly(3-alkylthiophene)s”, IEEE Transactions on Electron Device 51, 1982 (2004).
[25] A. Zen, J. Pflaum, S. Hirschmann, W. Zhuang, F. Jaiser, U. Asawapirom, J. P. Rabe, U. Scherf, D. Neher, “Effect of molecular weight and annealing of Poly(3-hexylthiophene)s on the performance of organic field-effect transistors”, Advanced Functional Materials 16, 1051 (2004)
[26] H. Sirringhaus, P. J. Brown, R. H. Friend, M. Nielsen, K. Bechgaard, B. M. W. Langeveld-Voss, A. J. H. Spiering, R. A. J. Janssen, E. W. Meijer, P. Herwig, D. M. de Leeuw, “Two-dimensional charge transport in self-organized, high-mobility conjugated polymers”, Nature 401, 685 (1999).
[27]G. Wang, J. Swensen, D. Moses, A. J. Heeger, “Increased mobility from regioregular poly(3-hexythiophene) field-effect transistor”, Journal of Applied Physics 93, 6137 (2003).
[28]D. H. Kim, Y. D. Park, Y. Jang, H. Yang, Y. H. Kim, J. I. Han, D. G. Moon, S. Park, T. Chang, C. Chang, M. Joo, C. Y. Ryu, K. Cho, “Enhancement of field-effect mobility by surface-mediated molecular ordering in regioregular polythiophene thin film transistor”, Advanced Functional Materials 15, 77 (2005).
[29] J. Veres, S. Ogier, G. Lloyd, “Gate insulators in organic field-effect transistors”, Chemistry of Materials 16, 4543 (2004).
[30] R. Osterbacka, C. P. An, X. M. Jiang, Z. V. Vardeny, “Two-dimensional electronic excitations in self-assembled conjugated polymer nanocrystals ”, Science 287, 34 (2000).
[31]http://en.wikipedia.org/wiki/Image:Polythiophenes_Crosscoupling.png
[32] K. E. Aasmundtveit, E. J. Samuelsen, M. Guldstein, C. Steinsland, O. Flornes, C. Fagermo, T. M. Seeberg, L. A. A. Pettersson, O. Inganas, R. Feidenhans’l, S. Ferrer, “Structural anisotropy of poly(alkylthiophene) films”, Macromolecules 33, 3120 (2000).
[33] 羅蕙蕙, 工業技術研究院, 水性PU原理講義.
[34] http://www.techbank.com.tw/PVD-process-introduction.htm
[35] 汪建民, “材料分析”, 中國材料科學學會, 第四版 (2005)
[36]. 成大微奈米中心四點探針講義.
http://airp.org.tw/SOP/NCKU/SOP%204-Point%20Probe.pdf
[37] J. Ouyng, C. W. Chu, F. C. Chen, Q. Xu, Y. Yang, “High-conductivity poly(3,4-Ethylenedioxythiophene):poly(styrene sulfonate) film and its application in polymer optoelectronic devices”, Advanced Functional Materials 15, 32 (2005).
[38] Y. W. Wang, H. L. Cheng, Y. K. Wang, T. H. Hu, J. C. Ho, C. C. Lee, T. F. Lei, C. F. Yeh, ” Influence of measuring environment on the electrical characteristics of pentacene-based thin film transistors” Thin Solid Films 467, 215 (2004)
[39] 林士廷, “有機光電元件之製程設計與載子傳輸機制之探討”, 博士 論文, 國立成功大學 (2007)
[40] P. V. Necliudov, M. S. Shur, D. J. Gundlach, T. N. Jackson, “Contact resistance extraction in pentacene thin film transistors”, Solid-State Electronics 47, 259 (2003).
[41] H. Klauk, G. Schmid, W. Radlik, W. Weber, L. Zhou, C. D. Sheraw, J. A. Nichols, T. N. Jackson, “Contact resistance in organic thin film transistors”, Solid-State Electronics 47, 297 (2003).
[42] D. R. Gamota, P. Brazis, K. Kalyanasundaram, J. Zhang, “Printed organic and molecular electronics”, Kluwer Academic Publishers, Norwell (2004).