本論文主要探討有機薄膜電晶體的最佳化與磁電導效應。第一部份討論有機自組裝分子膜表面修飾對顛倒共平面元件的影響，針對氧化層及金屬層分別及共同修飾電洞傳輸及注入進行探討，藉由合適的表面修飾可提升載子遷移率並降低接觸電阻，並且藉由表面分析得知五環素顆粒變大且排列變得聚集，所以我們可以藉由有機自組裝分子膜表面修飾提升元件表現。第二部份探討有機薄膜電晶體照光產生正磁電導響應的機制模型並驗證，根據物理理論及元件特性排除單重態激發子解離之可能性，並藉由改變閘極電壓排除三重態激發子與電荷反應之可能性，接著改變通道長及五環素厚度驗證正磁電導來自於三重態激發子解離。最後進一步驗證正磁電導響應和五環素激發內部三重態激發子的數量相關。藉此讓我們對於有機場效電晶體磁電導效應的機制有更深入的瞭解。

We investigate optimizing pentacene-based field-effect transistors (FETs) and its magnetoconductance (MC) responses. Firstly, we focus on the self-assembled monolayers (SAMs) contact surface treatment methods for bottom contact/bottom gate FETs. We discuss how the surface modifications of both the gate dielectrics and gold electrodes influence the morphology and electrical properties. SAMs of both of octadecyltrichlorosilane (OTS) and various aromatic organothiols is used to selectively modify surface. As the results, the sample treated with SAMs improves carrier mobility and contact resistance.
Secondly, we study on the positive magnetoconductance (MC) under low applied magnetic field and irradiation in top contact/bottom gate FETs. From physical interpretations and theoretical models of organic spintronics, we guess the effect is from triplet exciton-charge reaction or triplet dissociation. Besides, we excluded the triplet exciton-charge reaction model by changing gate voltage. By changing the channel length and pentacene thickness, we propose the effect is from the triplet dissociation. In addition, we further confirm that the MC is determined by the density of triplet, which is correlated to the absorption of pentacene. In conclusion, we attributed the observed photoinduced positive MC in pentacene-based FET to the triplet dissociation.

1.C. K. Chiang, C. R. Fincher, Jr., Y. W. Park, A. J. Heeger, H. Shirakawa, E. J. Louis, S. C. Gau and A. G. MacDiarmid, "Electrical conductivity in doped polyacetylene," Physical Review Letters, 39 (17), 1098-1101 (1977).
2. H. Koezuka, A. Tsumura and T. Ando, "Field-effect transistor with polythiophene thin film," Synthetic Metals, 18 (1–3), 699-704 (1987).
3. G. Horowitz, D. Fichou, X. Peng, Z. Xu and F. Garnier, "A field-effect transistor based on conjugated alpha-sexithienyl," Solid State Communications, 72 (4), 381-384 (1989).
4. Y. Y. Lin, D. J. Gundlach, S. F. Nelson and T. N. Jackson, "Stacked pentacene layer organic thin-film transistors with improved characteristics," Electron Device Letters, IEEE, 18 (12), 606-608 (1997).
5. H. Klauk, "Organic thin-film transistors," Chemical Society Reviews, 39 (7), 2643-2666 (2010).
6. C. W. Tang and S. A. VanSlyke, "Organic electroluminescent diodes," Applied Physics Letters, 51 (12), 913-915 (1987).
7. D. H. Kim, N. Lu, R. Ma, Y. S. Kim, R. H. Kim, S. Wang, J. Wu, S. M. Won, H. Tao, A. Islam, K. J. Yu, R. Chowdhury, M. Ying, L. Xu, M. Li, H. J. Chung, H. Keum, M. McCormick, P. Liu, Y. W. Zhang, F. G. Omenetto, Y. Huang, T. Coleman and J. A. Rogers, "Epidermal electronics," Science, 333 (6044), 838-843 (2011).
8. J. Zaumseil and H. Sirringhaus, "Electron and ambipolar transport in organic field-effect transistors," Chemical Reviews, 107 (4), 1296-1323 (2007).
9. J. A. Howarter and J. P. Youngblood, "Optimization of silica silanization by 3-aminopropyltriethoxysilane," Langmuir, 22 (26), 11142-11147 (2006).
10. M. E. McGovern, K. M. R. Kallury and M. Thompson, "Role of solvent on the silanization of glass with octadecyltrichlorosilane," Langmuir, 10 (10), 3607-3614 (1994).
11. S. Khodabakhsh, D. Poplavskyy, S. Heutz, J. Nelson, D. D. C. Bradley, H. Murata and T. S. Jones, "Using self-assembling dipole molecules to improve hole injection in conjugated polymers," Advanced Functional Materials, 14 (12), 1205-1210 (2004).
12. B. Choi, J. Rhee and H. H. Lee, "Tailoring of self-assembled monolayer for polymer light-emitting diodes," Applied Physics Letters, 79 (13), 2109-2111 (2001).
13. W. C. Bigelow, D. L. Pickett and W. A. Zisman, "Oleophobic monolayers: I. Films adsorbed from solution in non-polar liquids," Journal of Colloid Science, 1 (6), 513-538 (1946).
14. R. G. Nuzzo and D. L. Allara, "Adsorption of bifunctional organic disulfides on gold surfaces," Journal of the American Chemical Society, 105 (13), 4481-4483 (1983).
15. P. Fontaine, D. Goguenheim, D. Deresmes, D. Vuillaume, M. Garet and F. Rondelez, "Octadecyltrichlorosilane monolayers as ultrathin gate insulating films in metal-insulator-semiconductor devices," Applied Physics Letters, 62 (18), 2256-2258 (1993).
16. J. Collet and D. Vuillaume, "Nano-field effect transistor with an organic self-assembled monolayer as gate insulator," Applied Physics Letters, 73 (18), 2681-2683 (1998).
17. D. J. Gundlach, L. L. Jia and T. N. Jackson, "Pentacene TFT with improved linear region characteristics using chemically modified source and drain electrodes," Electron Device Letters, IEEE, 22 (12), 571-573 (2001).
18. I. Kymissis, C. D. Dimitrakopoulos and S. Purushothaman, "High-performance bottom electrode organic thin-film transistors," Electron Devices, IEEE Transactions on, 48 (6), 1060-1064 (2001).
19. H. Yang, T. J. Shin, M. M. Ling, K. Cho, C. Y. Ryu and Z. Bao, "Conducting AFM and 2D GIXD studies on pentacene thin films," Journal of the American Chemical Society, 127 (33), 11542-11543 (2005).
20. J. Kalinowski, M. Cocchi, D. Virgili, P. Di Marco and V. Fattori, "Magnetic field effects on emission and current in Alq3-based electroluminescent diodes," Chemical Physics Letters, 380 (5–6), 710-715 (2003).
21. M. Nishioka, Y. B. Lee, A. M. Goldman, Y. Xia and C. D. Frisbie, "Negative magnetoresistance of organic field effect transistors," Applied Physics Letters, 91 (9), 092117-3 (2007).
22. T. Reichert and T. P. I. Saragi, "Photoinduced magnetoresistance in organic field-effect transistors," Applied Physics Letters, 98 (6), 063307-3 (2011).
23. T. P. I. Saragi and T. Reichert, "Magnetic-field effects in illuminated tetracene field-effect transistors," Applied Physics Letters, 100 (7), 073304-4 (2012).
24. J. Youn, G. R. Dholakia, H. Huang, J. W. Hennek, A. Facchetti and T. J. Marks, "Influence of thiol self-assembled monolayer processing on bottom-contact thin-film transistors based on n-type organic semiconductors," Advanced Functional Materials, 22 (9), 1856-1869 (2012).
25. H. Wang, J. Wang, X. Yan, J. Shi, H. Tian, Y. Geng and D. Yan, "Ambipolar organic field-effect transistors with air stability, high mobility, and balanced transport," Applied Physics Letters, 88 (13), 133508-3 (2006).
26. W. Brutting and C. Adachi, "Physics of organic semiconductors," Wiley-VCH, Weinheim, FRG (2005).
27. N. Karl and J. Marktanner, "Electron and hole mobilities in high purity anthracene single crystals," Molecular crystals and liquid crystals science and technology. section A. molecular crystals and liquid crystals, 355 (1), 149-173 (2001).
28. S. M. Sze, "Semiconductor device: physics and technology, 2nd edition," Wiley, New York (2001).
29. M. Pope and C. E. Swenberg, "Elctronic processes in organic crystals and polymers, 2nd edition," Oxford University Press, New York (1999).
30. G. Horowitz, "Organic field-effect transistors," Advanced Materials, 10 (5), 365-377 (1998).
31. J. Veres, S. Ogier, G. Lloyd and D. de Leeuw, "Gate insulators in organic field-effect transistors," Chemistry of Materials, 16 (23), 4543-4555 (2004).
32. M. Marinkovic, D. Belaineh, V. Wagner and D. Knipp, "On the origin of contact resistances of organic thin film transistors," Advanced Materials, 24 (29), 4005-4009 (2012).
33. S. C. Lim, S. H. Kim, J. H. Lee, M. K. Kim, D. J. Kim and T. Zyung, "Surface-treatment effects on organic thin-film transistors," Synthetic Metals, 148 (1), 75-79 (2005).
34. M. Shtein, J. Mapel, J. B. Benziger and S. R. Forrest, "Effects of film morphology and gate dielectric surface preparation on the electrical characteristics of organic-vapor-phase-deposited pentacene thin-film transistors," Applied Physics Letters, 81 (2), 268-270 (2002).
35. J. C. Love, L. A. Estroff, J. K. Kriebel, R. G. Nuzzo and G. M. Whitesides, "Self-assembled monolayers of thiolates on metals as a form of nanotechnology," Chemical Reviews, 105 (4), 1103-1170 (2005).
36. A. Ulman, "Formation and structure of self-assembled monolayers," Chemical Reviews, 96 (4), 1533-1554 (1996).
37. F. Schreiber, A. Eberhardt, T. Y. B. Leung, P. Schwartz, S. M. Wetterer, D. J. Lavrich, L. Berman, P. Fenter, P. Eisenberger and G. Scoles, "Adsorption mechanisms, structures, and growth regimes of an archetypal self-assembling system: decanethiol on Au(111)," Physical Review B, 57 (19), 12476-12481 (1998).
38. C. D. Bain, E. B. Troughton, Y. T. Tao, J. Evall, G. M. Whitesides and R. G. Nuzzo, "Formation of monolayer films by the spontaneous assembly of organic thiols from solution onto gold," Journal of the American Chemical Society, 111 (1), 321-335 (1989).
39. H. E. Katz, J. Johnson, A. J. Lovinger and W. Li, "Naphthalenetetracarboxylic diimide-based n-channel transistor semiconductors:  structural variation and thiol-enhanced gold contacts," Journal of the American Chemical Society, 122 (32), 7787-7792 (2000).
40. M. L. Swiggers, G. Xia, J. D. Slinker, A. A. Gorodetsky, G. G. Malliaras, R. L. Headrick, B. T. Weslowski, R. N. Shashidhar and C. S. Dulcey, "Orientation of pentacene films using surface alignment layers and its influence on thin-film transistor characteristics," Applied Physics Letters, 79 (9), 1300-1302 (2001).
41. G. R. Dholakia, M. Meyyappan, A. Facchetti and T. J. Marks, "Monolayer to multilayer nanostructural growth transition in n-type oligothiophenes on Au(111) and implications for organic field-effect transistor performance," Nano Letters, 6 (11), 2447-2455 (2006).
42. W. Wang, T. Lee and M. A. Reed, "Elastic and inelastic electron tunneling in alkane self-assembled monolayers," The Journal of Physical Chemistry B, 108 (48), 18398-18407 (2004).
43. C. Bock, D. V. Pham, U. Kunze, D. Kafer, G. Witte and C. Woll, "Improved morphology and charge carrier injection in pentacene field-effect transistors with thiol-treated electrodes," Journal of Applied Physics, 100 (11), 114517-7 (2006).
44. C. D. Zangmeister, S. W. Robey, R. D. van Zee, J. G. Kushmerick, J. Naciri, Y. Yao, J. M. Tour, B. Varughese, B. Xu and J. E. Reutt-Robey, "Fermi level alignment in self-assembled molecular layers:  the effect of coupling chemistry," The Journal of Physical Chemistry B, 110 (34), 17138-17144 (2006).
45. J.-P. Hong, A.-Y. Park, S. Lee, J. Kang, N. Shin and D. Y. Yoon, "Tuning of Ag work functions by self-assembled monolayers of aromatic thiols for an efficient hole injection for solution processed triisopropylsilylethynyl pentacene organic thin film transistors," Applied Physics Letters, 92 (14), 143311-3 (2008).
46. G. S. Tulevski, Q. Miao, A. Afzali, T. O. Graham, C. R. Kagan and C. Nuckolls, "Chemical complementarity in the contacts for nanoscale organic field-effect transistors," Journal of the American Chemical Society, 128 (6), 1788-1789 (2006).
47. S. Gowrisanker, Y. Ai, M. A. Quevedo-Lopez, H. Jia, H. N. Alshareef, E. Vogel and B. Gnade, "Impact of semiconductor/contact metal thickness ratio on organic thin-film transistor performance," Applied Physics Letters, 92 (15), 153305-3 (2008).
48. B. Hu, L. Yan and M. Shao, "Magnetic-field effects in organic semiconducting materials and devices," Advanced Materials, 21 (14-15), 1500-1516 (2009).
49. H. Klauk, M. Halik, U. Zschieschang, G. Schmid, W. Radlik and W. Weber, "High-mobility polymer gate dielectric pentacene thin film transistors," Journal of Applied Physics, 92 (9), 5259-5263 (2002).
50. D. J. Gundlach, J. Li Li and T. N. Jackson, "Pentacene TFT with improved linear region characteristics using chemically modified source and drain electrodes," Electron Device Letters, IEEE, 22 (12), 571-573 (2001).
51. Y. K. Su, M. L. Tu, A. C. Wang, Y. S. Chen, Y. Z. Chiou, Y. T. Chiou and C. H. Chu, "Interface modification in organic thin film transistors," Japanese Journal of Applied Physics, 44 (4B), 2783-6 (2005).
52. P. Desai, P. Shakya, T. Kreouzis and W. P. Gillin, "Magnetoresistance in organic light-emitting diode structures under illumination," Physical Review B, 76 (23), 235202-5 (2007).
53. C. Jundt, G. Klein, B. Sipp, J. Le Moigne, M. Joucla and A. A. Villaeys, "Exciton dynamics in pentacene thin films studied by pump-probe spectroscopy," Chemical Physics Letters, 241 (1–2), 84-88 (1995).
54. M. W. B. Wilson, A. Rao, J. Clark, R. S. S. Kumar, D. Brida, G. Cerullo and R. H. Friend, "Ultrafast dynamics of exciton fission in polycrystalline pentacene," Journal of the American Chemical Society, 133 (31), 11830-11833 (2011).