本文研究五苯有機薄膜電晶體雙載子特性，第一部分探討五苯有機薄膜電晶體的接觸電阻與通道電阻，第二部分探討不同高分子修飾層對五苯有機薄膜電晶體雙載子特性影響。
第一部分研究元件通道長度對五苯元件的雙載子特性影響。隨著元件通道長度增加，飽和載子遷移率上升，起始電壓增大。在飽和區，隨著閘極偏壓增加或汲極偏壓下降，五苯元件的接觸電阻與通道電阻減小。接觸電阻在雙載子五苯元件的電特性是一個重要因素。
第二部分研究變化不同高分子修飾層對五苯元件雙載子特性影響。利用配製不同濃度的高分子溶液，以旋轉塗佈方式製作高分子修飾層。發現高分子修飾層材料與溶液的濃度條件，嚴重影響元件雙載子特性，然而，修飾層厚度並非掌控雙載子特性的主因。改變元件內五苯主動層厚度，也會影響元件的雙載子特性，包括：起始電壓、輸出曲線起始行為和關閉電流等影響。若進一步利用氧電漿處理元件修飾層，將使元件由雙載子特性轉變為電洞傳輸的單載子特性；若以氧電漿處理五苯主動層，則可改善元件p型輸出曲線起始行為。綜合而論，製作雙載子有機電晶體元件時，元件內的每個組件的製程條件均須謹慎評估，將有助於擴展其在相當電子產品的應用面。

We have studied the ambipolar properties of pentacene-based organic thin-film transistors (Pen-OTFTs). In the first part, the contact resistance and channel resistance of Pen-OTFTs were investigated. In the second part, the ambipolar characteristics of Pen-OTFTs with different polymer modification layers were studied.
In part 1, we studied the influence of channel length on the ambipolar properties of Pen-OTFTs. With increasing channel length, we observed an increase in the saturated mobilities, and the threshold voltage becomes enlarged. In the saturation region, the contact resistance and channel resistance of Pen-OTFTs decreased with increasing gate bias or decreasing drain bias. Contact resistance plays an important role in the electrical properties of ambipolar pen-OTFTs.
Part 2 focused on an investigation of the influences of various different polymer modification layers on the ambipolar properties of Pen-OTFTs. The polymer modification layers were prepared via solution deposition with a spin-coating technique using different solvents that have various polymer concentrations. We found that the ambipolar properties are highly dependent on the polymer materials and preparation methods of these polymer modification layers. In contrast, we did not observe any considerable effects from the thickness of the modification layers on the ambipolar properties. Yet, we observed a significant influence of the thickness of the pentacene active layer on the ambipolar properties, including the threshold voltage, the threshold behaviors in the output current, and the off-current. On the other hand, when polymer modification layers were treated with oxygen plasma, the pen-OTFTs lost their ambipolar properties, thereby leaving unipolar hole properties. In addition, when the pentacene layers were treated with oxygen plasma, the non-ideal threshold behaviors in the output current were further improved.

[1] M. Pope, C. E. Swenberg, Electronic Processes in Organic Crystals and Polymers, 2nd ed., Oxford University Press, Oxford 1999, pp. 337-340.

[2] C. W. Tang, S. A. VanSlyke, “Organic electroluminescent diodes”, Appl. Phys. Lett., 51, 913, 1987.

[3] L. Wang, Y. Jiang, J. Luo, Y. Zhou, J. Zhou, J. Wang, J. Pei, Y. Cao, “Highly Efficient and Color-Stable Deep-Blue Organic Light-Emitting Diodes Based on a Solution-Processible Dendrimer”, Adv. Mater., 21, 4854, 2009.

[4] C. W. Tang, “Two-layer organic photovoltaic cell”, Appl. Phys. Lett., 48, 183, 1986.

[5] J. W. Jung, J. U. Lee, W. H. Jo, “High-Efficiency Polymer Solar Cells with Water-Soluble and Self-Doped Conducting Polyaniline Graft Copolymer as Hole Transport Layer”, J. Phys. Chem. C, 114, 633, 2010.

[6] A. Tsumura, H. Koezuka, T. Ando, “Macromolecular electronic device: Field-effect transistor with a polythiophene thin film”, Appl. Phys. Lett., 49, 1210, 1986.

[7] D. S. Chung, J. W. Park, J. H. Park, D. Moon, G. H. Kim, H. S. Lee, D. H. Lee, H. K. Shim, S. K. Kwon, C. E. Park, “High mobility organic single crystal transistors based on soluble triisopropylsilylethynyl anthracene derivatives”, J. Mater. Chem., 20, 524, 2010.

[8] C. F. Sung, D. Kekuda, L. F. Chu, Y. Z. Lee, F. C. Chen, M. C. Wu, C. W. Chu, “Flexible Fullerene Field-Effect Transistors Fabricated Through Solution Processing”, Adv. Mater., 21, 4845, 2009.

[9] C. D. Dimitrakopoulos, P. R. L. Malenfant, “Organic Thin Film Transistors for Large Area Electronics”, Adv. Mater., 14, 99, 2002.

[10] T. Someya, Y. Kato, S. Iba, Y. Noguchi, T. Sekitani, H. Kawaguchi, T. Sakurai, “Integration of Organic FETs With Organic Photodiodes for a Large Area, Flexible, and Lightweight Sheet Image Scanners”, IEEE Trans. Electron Devices, 52, 2502, 2005.

[11] C. S. Jones, X. Lu, M. Renn, M. Stroder, W. S. Shih, “Aerosol-jet-printed, high-speed, flexible thin-film transistor made using single-walled carbon nanotube solution”, Microelectronic Engineering, 87, 434, 2010.

[12] R. C. G. Naber, K. Asadi, P. W. M. Blom, D. M. de Leeuw, B. de Boer, “Organic Nonvolatile Memory Devices Based on Ferroelectricity”, Adv. Mater., 21, 1, 2009.

[13] I. Yagi, N. Hirai, Y. Miyamoto, M. Noda, A. Imaoka, N. Yoneya, K. Nomoto, J. Kasahara, A. Yumoto, T. Urabe, “A flexible full-color AMOLED display driven by OTFTs”, Journal of the SID 16/1, 2008.

[14] B. Crone, A. Dodabalapur, Y.-Y. Lin, R. W. Filas, Z. Bao, A. LaDuca, R. Sarpeshkar, H. E. Katz, W. Li, “Large-scale complementary integrated circuits based on organic transistors”, Nature, 403, 521, 2000.

[15] B. Crone, A. Dodabalapur, A. Gelperin, L. Torsi, H. E. Katz, A. J. Lovinger, Z. Bao, “Electronic sensing of vapors with organic transistors”, Appl. Phys. Lett., 78, 2229, 2001.

[16] P. F. Baude, D. A. Ender, M. A. Haase, T. W. Kelley, D. V. Muyres, S. D. Theiss, “Pentacene-based radio-frequency identification circuitry”, Appl. Phys. Lett., 82, 3964, 2003.

[17] R. Ye, M. Baba, K. Suzuki, Y. Ohishi, K. Mori, “Effects of O2 and H2O on electrical characteristics of pentacene thin film transistors”, Thin Solid Films, 464, 437, 2004.

[18] S. D. Wang, T. Minari, T. Miyadera, Y. Aoyagi, K. Tsukagoshi, “Bias stress instability in pentacene thin film transistors: Contact resistance change and channel threshold voltage shift”, Appl. Phys. Lett., 92, 063305, 2008.

[19] I. Kymissis, Student Member, IEEE, C. D. Dimitrakopoulos, S. Purushothaman, “High-Performance Bottom Electrode Organic Thin-Film Transistors”, IEEE Trans. Electron Devices, 48, 1060, 2001.

[20] C.-Y. Yang, Dhananjay, S.-S. Cheng, C.-W. Ou, Y.-C. Chuang, M.-C. Wu, C.-W. Chu, “Balancing the ambipolar conduction for pentacene thin film transistors through bifunctional electrodes”, Appl. Phys. Lett., 92, 253307, 2008.

[21] H. Yan, T. Kagata, H. Okuzaki, “Ambipolar pentacene/C60-based field-effect transistors with high hole and electron mobilities in ambient atmosphere”, Appl. Phys. Lett., 94, 023305, 2009.

[22] J. Huang, M. Yi, I. A. Hummelgen, D. Ma, “Ambipolar permeable metal-base transistor based on NPB/C60 heterojunction”, Organic Electronics, 10, 210, 2009.

[23] M. Schidleja, C. Melzer, H. von Seggern, “Investigation of Charge- Carrier Injection in Ambipolar Organic Light-Emitting Field-Effect Transistors”, Adv. Mater., 21, 1172, 2009.

[24] J.-H. Kwak, H.-I. Baek, C. Lee, “Ambipolar pentacene field-effect transistor with double-layer organic insulator”, Proc. of SPIE, 6336, 63361C, 2006.

[25] T. B. Singh, F. Meghdadi, S. Gunes, N. Marjanovic, G. Horowitz, P. Lang, S. Bauer, N. S. Sariciftci, “High-Performance Ambipolar Pentacene Organic Field-Effect Transistors on Poly(vinyl alcohol) Organic Gate Dielectric”, Adv. Mater., 17, 2315, 2005.

[26] Y. Wang, R. Kumashiro, R. Nouchi, N. Komatsu, K. Tanigaki, “Influence of interface modifications on carrier mobilities in rubrene single crystal ambipolar field-effect transistors”, J. Appl. Phys., 105, 124912, 2009.

[27] C. Rost, D. J. Gundlach, S. Karg, W. Rieß, “Ambipolar organic field-effect transistor based on an organic heterostructure”, J. Appl. Phys., 95, 5782, 2004.

[28] H. Wang, J. Wang, X. Yan, J. Shi, H. Tian, Y. Geng, D. Yan, “Ambipolar organic field-effect transistors with air stability, high mobility, and balanced transport”, Appl. Phys. Lett., 88, 133508, 2006.

[29] M. Shibao, T. Morita, W. Takashima, K. Kaneto, “Ambipolar Transport in Field-Effect Transistors Based on Composite Films of Poly(3-hexylthiophene) and Fullerene Derivative”, Jpn. J. Appl. Phys., 46, L123, 2007.

[30] T. Kaji, S. Entani, S. Ikeda, K. Saiki, “Origin of Carrier Types in Intrinsic Organic Semiconductors”, Adv. Mater., 20, 2084, 2008.

[31] G. Horowitz, “Organic Field-Effect Transistors”, Adv. Mater., 10, 365, 1998.

[32]施敏著，黃調元譯，“半導體元件物理與製作技術(第二版)”，2006.

[33] R. Schmechel, M. Ahles, H. von Seggern, “A pentacene ambipolar transistor: Experiment and theory”, J. Appl. Phys., 98, 084511, 2005.

[34] P. V. Necliudov, M. S. Shur, D. J. Gundlach, T. N. Jackson,“Contact resistance extraction in pentacene thin film transistors”, Solid-State Electron., 47, 259, 2003.

[35] 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 Electron., 47, 297, 2003.

[36] K. Seshadri, C. D. Frisbie, “Potentiometry of an operating organic semiconductor field-effect transistor”, Appl. Phys. Lett., 78, 993, 2001.

[37] M.-H. Yoon, C. Kim, A. Facchetti, T. J. Marks, “Gate Dielectric Chemical Structure-Organic Field-Effect Transistor Performance Correlations for Electron, Hole, and Ambipolar Organic Semiconductors”, J. Am. Chem. Soc., 128, 12851, 2006.

[38] S. Steudel, S. D. Vusser, S. D. Jonge, D. Janssen, S. Verlaak, J. Genoe, P. Heremans, “Influence of the dielectric roughness on the performance of pentacene transistors”, Appl. Phys. Lett., 85, 4400, 2004.

[39] L.-L. Chua, J. Zaumseil, J.-F. Chang, E. C.-W. Ou, P. K.-H. Ho, H. Sirringhaus, R. H. Friend, “General observation of n-type field-effect behaviour in organic semiconductors”, Nature, 434, 194, 2005.

[40] S.-i. Noro, T. Takenobu, Y. Iwasa, H.-C. Chang, S. Kitagawa, T. Akutagawa, T. Nakamura, “Ambipolar, Single-Component, Metal–Organic Thin-Film Transistors with High and Balanced Hole and Electron Mobilities”, Adv. Mater., 20, 3399, 2008.

[41] D. L. Smith, P. P. Ruden, “Analytic device model for light-emitting ambipolar organic semiconductor field-effect transistors”, Appl. Phys. Lett., 89, 233519, 2006.

[42] S. Y. Kim, T. Ahn, S. Pyo, M. Yi, “Surface modified polymeric gate insulators for pentacene organic thin-film transistors”, Current Applied Physics, 9, 913, 2009.

[43] Y. Yun, C. Pearson, M. C. Petty, “Pentacene thin film transistors with a poly(methyl methacrylate) gate dielectric: Optimization of device performance”, J. Appl. Phys., 105, 034508, 2009.

[44] H.-L. Cheng, Y.-S. Mai, W.-Y. Chou, L.-R. Chang, X.-W. Liang, “Thickness-Dependent Structural Evolutions and Growth Models in Relation to Carrier Transport Properties in Polycrystalline Pentacene Thin Films”, Adv. Funct. Mater., 17, 3639, 2007.

[45] L. Mariucci, D. Simeone, S. Cipolloni, L. Maiolo, A. Pecora, G. Fortunato, S. Brotherton, “Effect of active layer thickness on electrical characteristics of pentacene TFTs with PMMA buffer layer”, Solid-State Electronics, 52, 412, 2008.

[46] J.-M. Choi, S. Im, “Optimum channel thickness of rubrene thin-film transistors”, Appl. Phys. Lett., 93, 043309, 2008.

[47] N. Benson, M. Schidleja, C. Siol, C. Melzer, H. v. Seggern, “Dielectric interface modification by UV irradiation: a novel method to control OFET charge carrier transport properties”, Proc. of SPIE, 6658, 66580W, 2007.

[48] R. H. Hansen, J. V. Pascale, T. D. Benedictis, P. M. Rentzepis, “Effect of Atomic Oxygen on Polymers”, J. Polym. Sci. Pol. Chem., 3, 2205, 1965.

[49] K. C. Dickey, S. Subramanian, J. E. Anthony, L.-H. Han, S. Chen, Y.-L. Looa, “Large-area patterning of a solution-processable organic semiconductor to reduce parasitic leakage and off currents in thin-film transistors”, Appl. Phys. Lett., 90, 244103, 2007.

[50] P. S. Jo, J. Sung, C. Park, E. Kim, D. Y. Ryu, S. Pyo, H.-C. Kim, J. M. Hong, “Controlled Topology of Block Copolymer Gate Insulators by Selective Etching of Cylindrical Microdomains in Pentacene Organic Thin Film Transistors”, Adv. Funct. Mater., 18, 1202, 2008.