本論文主要探討缺陷態對負型五環素場效電晶體的影響。在本質缺陷中討論了五環素蒸鍍速率對電子流的影響，在雜質缺陷中討論了曝氧對電子流造成的衰退現象，最後並利用缺陷態密度計算分析之。在論文中更進一步利用照光激發的方式驗證缺陷態載子的存在，但卻觀察到在照光下出現由單載子到雙載子傳輸的轉換現象以及電子流隨照光時間衰減。針對此問題，在論文中試著提出照光下的載子傳輸模型並利用實驗驗證之。藉由此討論讓我們對於五環素在電子傳輸上有更深入的了解。

This study investigates the influence of the electronic trap states in pentacene-based organic field effect transistors (OFET) with pentacene as active layer, aluminum as source-drain electrodes, and polystyrene (PS) as dielectrics. It found that the different evaporated rates of pentacene are correlated with the amount of grain boundary which is consider as the intrinsic defects and affects the device characteristics. It also found the samples with exposing to oxygen resulting in the decay of electron mobility. This phenomenon ascribes to oxygen-related impurity defects. Both defects can be analyzed the trap density of sates by Kalb et al. In order to verify the existences of trap states, the photon excitation is a useful tool. But we observe a special phenomenon that the transformation from unipolar to ambipolar transport and the decay of electron flow under illumination. The ambipolar behavior and electron decay relate mainly to the trap states in electronic transport. This study provides insights of defects in channel, develops device structure and fabrication approaches, and evaluates the feasibility of n-type pentacene-based OFETs.

1.C. K. Chiang, C. B. Fincher, Y. W. Park, A. J. Heeger, H. Shirakawa, E. J. Louis, S. C. Gau, and A. G. MacDiarmid, “Electrical conductivity in doped polyacetylene,” Phys. Rev. Lett. 39(17), 1098-1101 (1977).

2.H. Koezuka, A. Tsumura, and T. Ando, “Field-effect transistor with polythiophene thin film,” Synth. Met. 18(1), 699-704 (1987).

3.Y. Y. Lin, D. J. Gundlach, S. F. Nelson, and T. N. Jackson, “Stacked pentacene layer organic thin-film transistors with improved characteristics,” IEEE Electron Dev. Lett. 18(12), 606-608 (1997).

4.H. Klauk, “Organic thin-film transistors,” Chem. Soc. Rev. 39(7), 2643-2666 (2010).

5.C. W. Tang and S. A. VanSlyke, “Organic electroluminescent diodes,” Appl. Phys. Lett. 51, 913 (1987).

6.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, T. I. Kim, 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).

7.L. L. Chua, J. Zaumseil, J. F. Chang, E. C. W. Ou, P. K. H. Ho, H. Sirringhaus, and R. H. Friend, “General observation of n-type field-effect behaviour in organic semiconductors,” Nature 434(7030), 194-199 (2005).

8.J. Zaumseil and H. Sirringhaus, “Electron and Ambipolar Transport in Organic Field-Effect Transistors,” Chem. Rev. 107(4), 1296-1323 (2007).

9.D. Jurchescu, M. Popinciuc, B. J. V. Wees, and T. T. M. Palstra, “Interface-controlled, high-mobility organic transistors,” Adv. Mater. (Deerfield Beach Fla.) 19(5), 688-692 (2007).

10.T. Yasuda, T. Goto, K. Fujita, and T. Tsutsui, “Ambipolar pentacene field-effect transistors with calcium source-drain electrodes,” Appl. Phys. Lett. 85, 2098 (2004).

11.T. B. Singh, F. Meghdadi, S. Günes, N. Marjanovic, G. Horowitz, P. Lang, S. Bauer, and N. S. Sariciftci,” High-performance ambipolar pentacene field-effect transistors on poly(vinyl alcohol) organic gate dielectric,” Adv. Mater. (Deerfield Beach Fla.) 17(19), 2315-2320 (2005).

12.J. W. Chang, W. L. Hsu, C. Y. Wu, T. F. Guo, T. C. Wen, “The polymer gate dielectrics and source-drain electrodes on n-type pentacene-based organic field-effect transistors,” Org. Electron. 11(10), 1613-1619 (2010).

13.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,” Appl. Phys. Lett. 88, 133508 (2006).

14.W. Brutting, “Physics of organic semiconductors,” Wiley-VCH, Weinheim, FRG (2006).

15.N. Karl and J. Marktanner, “Electron and hole mobilities in high purity anthracene single crystals,” Mol. Cryst. Liq. Cryst. Sci. Technol., Sect. A 355(1), 149-173 (2001).

16.S. M. Sze, “Semiconductor device：physics and technology, 2nd edition,” Wiley, New York (2001).

17.M. Pope and C. E. Swenberg, “Elctronic processes in organic crystals and polymers, 2nd edition,” Oxford University Press, New York (1999).

18.G. Horowitz, “Organic field-effect transistors,” Adv. Mater. (Deerfield Beach Fla.) 10(5), 365-377 (1998).

19.J. Veres, S. Ogier, and G. Lloyd, “Gate insulaters in organic field-effect transistors,” Chem. Mater. 16(23), 4543-4555 (2004).

20.J. Shi, H. Wang, D. Song, H. Tian, Y. Geng, and D. Yan, “n-channel, ambipolar, and p-channel organic heterojunction transistors fabricated with various film morphologies,” Adv. Funct. Mater. 17(3), 397-400 (2007).

21.R. Schmechel, M. Ahles, and H. V. Seggern, “A pentacene ambipolar transistor: Experiment and theory,” J. Appl. Phys. 98, 084511 (2005).

22.W. L. Kalb, S. Haas, C. Krellner, T. Mathis, and B. Batlogg, “Trap density of states in small-molecule organic semiconductors: A quantitative comparison of thin-film transistors with single crystals,” Phys. Rev. B 81,155315 (2010).

23.C. Kim, A. Facchetti, and T. J. Marks, “Gate dielectric microstructural control of pentacene film growth mode and field-effect transistor performance,” Adv. Mater. (Deerfield Beach Fla.) 19(18), 2561-2566 (2007).

24.H. Klauk, M. Halik, U. Zschieschang, G. Schmid, and W. Radlik, “High-mobility polymer gate dielectric pentacene thin film transistors,”
J. Appl. Phys. 92, 5259 (2002).

25.J. W. Chang, P. W. Liang, M. W. Lin, T. F. Guo, T. C. Wen, Y. J. Hsu, “An ambipolar to n-type transformation in pentacene-based organic field-effect transistors,” Org. Electron. 12(3), 509-515 (2011).

26.O. D. Jurchescu, J. Baas, and T. T. M. Palstra, “Effect of impurities on the mobility of single crystal pentacene,” Appl. Phys. Lett. 84, 3061 (2004).

27.A. Benor, D. Knipp, J. Northrup, A. R. Völkel, R. A. Street, “Influence of gap states on the electrical stability of pentacene thin film transistors,”
J. Non-Cryst. Solids 354(19-25), 2875-2878 (2008).

28.K. Lee, M. S. Oh, S. J. Mun, K. H. Lee, T. W. Ha, J. H. Kim, S. H. K. Park, C. S. Hwang, B. H. Lee, M. M. Sung, and S. Im, “Interfacial trap density-of-states in pentacene- and ZnO-based thin-film transistors measured via novel photo-excited charge-collection spectroscopy,” Adv. Mater. (Deerfield Beach Fla.) 22(30), 3260-3265 (2010).