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研究生：	陳建中 Chen, Chien-Chung
論文名稱：	利用Q-DLTS研究C60內之缺陷 Study of traps in fullerene(C60) by Q-DLTS
指導教授：	許渭州 Hsu, Wei-Chou
學位類別：	碩士 Master
系所名稱：	電機資訊學院 - 微電子工程研究所 Institute of Microelectronics
論文出版年：	2010
畢業學年度：	98
語文別：	英文
論文頁數：	79
中文關鍵詞：	Q-DLTS 、C60 、缺陷、退火、摻雜
外文關鍵詞：	Q-DLTS, C60, trap, annealing, doping
相關次數：	點閱：91 下載：0
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本篇論文中我們運用電荷式深能階暫態能譜(Q-DLTS)分析富勒烯(C60)中的缺陷，並量測在不同處理之下，例如：退火、老化、摻雜，對缺陷造成的改變，進一步分析這些改變將對元件的表現產生何種影響，最後透過其他量測方式，諸如：傅立葉轉換紅外線光譜儀(FTIR)、電流密度對電壓(J-V)量測、吸收光譜量測等，以及實際量測元件表現來佐證我們的分析結果。
首先是C60元件退火處理的部分，我們觀察到在85℃下退火15分鐘時能對缺陷有最大的改善，活化能(Ea)最淺(由0.11 eV降為0.02 eV)且缺陷濃度小(由4.84*1015 cm-3降為3.3*1015 cm-3)，故我們推測此時C60的移動率為最快，而變淺的活化能也可能提升整體元件的開路電壓，之後我們做了元件的J-V量測，發現在85℃下退火15分鐘時有最大的電流，由此可推測此時C60移動率為最快，另外也實際製作太陽能電池ITO/CuPc/C60/Al，退火後效率有所提升，而提升原因正是開路電壓的升高，與我們推測的結果相符。
再來是有關元件老化的研究，隨著元件放置時間的增加，缺陷會產生何種變化，造成這些變化的可能因素又是什麼，都是我們欲探討的目標，隨著元件放置時間增長，缺陷深度變深(由0.068 eV到0.14 eV)，缺陷濃度也增加(由1.51*1015 cm-3增為9.68*1015 cm-3)，可能影響原因推測為水氧的侵蝕，並藉由FTIR 觀察到氫、氧的鍵結隨時間增加明顯增強，藉此證實我們的推論無誤。
最後是關於摻雜的部分，我們試圖在C60之中摻雜另一種同為N型材料的PTCBI並觀察其對缺陷所造成之影響，我們發現摻雜後缺陷變淺(由0.137 eV 變為0.062 eV)，缺陷濃度變大(由2.76*1015 cm-3增為6.81*1015 cm-3)，不過最明顯的變化則是充電時間的增加(由1 ms增為100 ms)，由此我們推測材料移動率將大幅下降，因為PTCBI為一低移動率之材料(約10-6 cm2/v．s)，而C60為一高移動率材料(約10-1 cm2/v．s)，故摻雜越多PTCBI將影響整體移動率，我們透過J-V量測以及元件效率量測證實移動率的確因摻雜而下降，元件電流以及填滿因子也隨之下降，可證實我們的推論無誤，另外用元件吸收光譜來證明我們不同的摻雜比例的確有反應在元件吸收波段之上。
透過上述實驗可知我們已具備利用Q-DLTS準確分析材料中缺陷的能力，並能經由分析缺陷進一步預測元件的表現，希望往後能藉此技術找出能改善缺陷的方法，進一步提升元件的效能。

In this thesis we used charge-based deep level transient spectroscopy (Q-DLTS) to measure traps in fullerene (C60), and measured the variation of traps under different treatments, for example: annealing, decay, and doping; furthermore, we expected the influence of variation on device performance; last, we used other ways of measurement( say: Fourier Transform Infrared Spectroscopy (FTIR), J-V measurement, absorption wavelength measurement ) and measured the device performance to verify our expectation.
First, we annealed the C60 devices with different temperatures, we discovered annealing under 85℃, 15 minutes had the best improvement for the traps in C60, active energy (Ea) was shallowest (from 0.11 eV to 0.02 eV), and trap density was small (from 4.84*1015 cm-3 to 3.3*1015 cm-3), so we conjectured that the mobility is highest when annealing with 85℃, 15 minutes, and the shallowest Ea may enhance the open circuit voltage of device. Then, we measured the J-V curves for devices after each annealing temperature, and found out the device annealing with 85℃, 15 minutes had the highest current, which also means it had the highest mobility. Next, we made a solar cell ITO/CuPc/C60/Al. After annealing with 85℃, 15 minutes the conversion efficiency had been improved because of the enhanced open circuit voltage, and it fitted in with our expectation.
Second, we studied about the decay of device. What changes might occur on the traps and what caused the changes as the time we put devices became longer are all we wanted to figure out. The longer time we put devices, the deeper the trap state became (from 0.068 eV to 0.14 eV), the trap concentration became denser too (from 1.51*1015 cm-3 to 9.68*1015 cm-3). We thought it might be caused by humidity and oxygen. So we used FTIR to verified our expectation and found out that the bonds of oxygen and hydrogen obviously became stronger as putted time increased. The result confirmed our inference was correct.
Last was the doping part. We doped some PTCBI which was also an N-type material into our C60, and then we observed what changes had happened on the traps. We found out the trap state became shallower (from 0.137 eV to 0.062 eV), and the trap concentration became denser (from 2.76*1015 cm-3 to 6.81*1015 cm-3), but the most obvious difference was the increase of charging time (Tc) (from 1 ms to 100 ms). We thought that meant the mobility became lower, because PTCBI was a low mobility material (about 10-6 cm2/v．s). On the opposite, C60 was a high mobility material (about 10-1 cm2/v．s), so when we doped more PTCBI into C60, the average mobility became lower. From the J-V curves and the performance of device we could see the mobility actually decreased, and the fill factor and short circuit current density became smaller too. The result could verify our expectation. We also measured the absorption wavelength to insure the different doping ratio really made difference.
We could say that we already had the ability to analyze the trap in materials accurately from experiment results mentioned above. Moreover, to predict the performance of devices by the trap analysis, we hope that we could find out some methods to improve the traps and also improve the device performance by those methods.

Abstract (Chinese) I 
Abstract (English) III 
Acknowledgement VI 
Table captions IX 
Figure captions XI 
Chapter 1 Introduction 1 
1-1 History of organic optoelectronic device 1 
1-2 How do traps influence carriers transport in organic materials 1 
1-3 Methods to measure traps in organic materials 2 
1-4 Forming of the device for Q-DLTS measuring 3 
1-5 Measuring the variation of traps in C60 under different treatments 3 
Chapter 2 Charge-based deep level transient spectroscopy 4 
2-1 Defect 4 
2-2 Theorems of Q-DLTS measurement 4 
2-3 Calculation of Q-DLTS measurement 5 
2-4 Determination of the type of a trap 6 
Chapter 3 Fabrication of device 7 
Device fabrication process 7 
3-1 Pre-clean ITO glass 7 
3-2 ITO pattern etching 7 
3-3 O2 plasma treatment 8 
3-4 Thermal organic vaporizing 8 
Chapter 4 Experimental Results 10 
4-1 Measurement of device made from CMO 10 
4-2 Measurement of device made from our laboratory 12 
4-3 Measurement of device under different annealing conditions 15 
4-4 Investigation of relation between traps and device’s decay 19 
4-5 Measurement of traps in C60 under different doping ratio of PTCBI 22 
Chapter 5 Conclusion 25 
References 27 

Table captions 
Table 4-1.1 Nt of device ITO/ET5/Al with parameters: ΔV = 0.2 V, Tc = 0.3 ms. 10 
Table 4-1.2 Nt of device ITO/ET5/Al with parameters: ΔV = -0.2 V, Tc = 0.3 ms. 11 
Table 4-2.1 Nt of device ITO/C60/Al with parameters: ΔV = 1 V, Tc = 1 ms. 12 
Table 4-2.2 Nt of device ITO/C60/Al with parameters: ΔV = -4 V, Tc = 10 ms. 13 
Table 4-3.1 Nt of device ITO/C60/Al with parameters: ΔV = 1 V, Tc = 1 ms, 50℃. 15 
Table 4-3.2 Nt of device ITO/C60/Al with parameters: ΔV = 1 V, Tc = 1 ms, 75℃. 16 
Table 4-3.3 Nt of device ITO/C60/Al with parameters: ΔV = 1 V, Tc = 1 ms, 85℃. 16 
Table 4-3.4 Nt of device ITO/C60/Al with parameters: ΔV = 1 V, Tc = 1 ms, 100℃. 16 
Table 4-3.5 Performance of device ITO/CuPc/C60/Al 19 
Table 4-4.1 Nt of device ITO/C60/Al with parameters: ΔV = 1 V, Tc = 1 ms. 20 
Table 4-4.2 Nt of device ITO/C60/Al with parameters: ΔV = 1 V, Tc = 1 ms, 3.5 hr. 20 
Table 4-4.3 Nt of device ITO/C60/Al with parameters: ΔV = 1 V, Tc = 1 ms, 7 hr. 20 
Table 4-4.4 Nt of device ITO/C60/Al with parameters: ΔV = 1 V, Tc = 1 ms, 11 hr. 21 
Table 4-4.5 Nt of device ITO/C60/Al with parameters: ΔV = 1 V, Tc = 1 ms, 15 hr. 21 
Table 4-5.1 Nt of device ITO/C60:PTCBI/Al with parameters: ΔV = 0.15 V 22 
Table 4-5.2 Performance of device ITO/CuPc/C60:PTCBI(X%)/BCP/Al 24 

Figure captions 
Fig. 1-1 Sketch of electron and hole traps in organic material 30 
Fig. 2-1 Principle and experimental parameters used in Q-DLTS technique 32 
Fig. 3-1 The diagram of high vacuum for organic thermal evaporator system 33 
Fig. 4-1.1 CMO device ITO/ET5(60nm)/Al(100nm) 34 
Fig. 4-1.2 Q-DLTS plots 35 
Fig. 4-1.3 Experimental parameters used in our measurement for ET5 36 
Fig. 4-1.4 Device ITO/ET5/Al with parameters: Tc = 0.3 ms, ΔV = 0.2 V 37 
Fig. 4-1.5 Device ITO/ET5/Al with parameters: Tc = 0.3 ms, ΔV = -0.2 V 38 
Fig. 4-1.6 Device ITO/ET5/Al with Tc = 0.3 ms 39 
Fig. 4-1.7 Energy band diagram of device ITO/ET5/Al 40 
Fig. 4-2.1 Tc plots 41 
Fig. 4-2.2 Experimental parameters used in our measurement for C60 42 
Fig. 4-2.3 Device ITO/C60/Al with parameters: Tc = 1 ms, ΔV = 1 V 43 
Fig. 4-2.6 Energy band diagram of device ITO/C60/Al 46 
Fig. 4-3.1 Device ITO/C60/Al with parameters: Tc = 1 ms, ΔV = 1 V, annealing 50℃, 15min 47 
Fig. 4-3.2 Device ITO/C60/Al with parameters: Tc = 1 ms, ΔV = 1 V, annealing 75℃, 15min 48 
Fig. 4-3.3 Device ITO/C60/Al with parameters: Tc = 1 ms, ΔV = 1 V, annealing 85℃, 15min 49 
Fig. 4-3.4 Device ITO/C60/Al with parameters: Tc = 1 ms, ΔV = 1 V, annealing 100℃, 15min 50 
Fig. 4-3.5 Device ITO/C60/Al with parameters: Tc = 1 ms, ΔV = 1 V, annealing 125℃, 15min 51 
Fig. 4-3.6 J-V curves of Device ITO/C60/Al 52 
Fig. 4-3.7 J-V curve of Device ITO/C60/Al 53 
Fig. 4-3.8 Device performances after different annealing temperature by [10] 54 
Fig. 4-3.9 Device structure 54 
Fig. 4-4.1 Device ITO/C60/Al with parameters: Tc = 1 ms, ΔV = 1 V 55 
Fig. 4-4.2 Device ITO/C60/Al with parameters: Tc = 1 ms, ΔV = 1 V, put 3.5 hr 56 
Fig. 4-4.3 Device ITO/C60/Al with parameters: Tc = 1 ms, ΔV = 1 V, put 7 hr 57 
Fig. 4-4.4 Device ITO/C60/Al with parameters: Tc = 1 ms, ΔV = 1 V, put 11 hr 58 
Fig. 4-4.5 Device ITO/C60/Al with parameters: Tc = 1 ms, ΔV = 1 V, put 15 hr 59 
Fig. 4-4.6 J-V curves of Device ITO/C60/Al 60 
Fig. 4-4.7 J-V curves of Device ITO/C60/Al 61 
Fig. 4-4.8 J-V curve of Device ITO/C60/Al 62 
Fig. 4-4.9 Relative mobility with different decay times 62 
Fig. 4-4.10 FTIR plot with different decay times 63 
Fig. 4-4.11 FTIR plot with different decay times 64 
Fig. 4-4.12 Some characteristics of frequencies with regard to different functional groups 65 
Fig. 4-5.1 Experimental parameters used in our measurement 66 
Fig. 4-5.2 Tc plots 67 
Fig. 4-5.3 Device ITO/C60/Al with parameters: Tc = 1 ms, ΔV = 0.15 V 68 
Fig. 4-5.4 Experimental parameters used in our measurement 69 
Fig. 4-5.5 Tc plots 70 
Fig. 4-5.6 Device ITO/C60/Al with parameters: Tc = 1 ms, ΔV = 0.15 V, doping 20% 71 
Fig. 4-5.7 Experimental parameters used in our measurement 72 
Fig. 4-5.8 Tc plots 73 
Fig. 4-5.9 Device ITO/C60/Al with parameters: Tc = 1 ms, ΔV = 0.15 V, doping 60% 74 
Fig. 4-5.10 Experimental parameters used in our measurement 75 
Fig. 4-5.11 Tc plots 76 
Fig. 4-5.12 Device ITO/C60/Al with parameters: Tc = 1 ms, ΔV = 0.15 V, doping 100% 77 
Fig. 4-5.13 Absorption of device ITO/C60/Al doping with different ratio of PTCBI 78 
Fig. 4-5.14 J-V curves of device ITO/C60/Al doping with different ratio of PTCBI 78 
Fig. 4-5.15 device structure (X = 0, 20, 60, 100) 79 
Fig. 4-5.16 device efficiency 79 
                                    

[1] M. Vogel, S. Doka, Ch. Breyer, M. Ch. Lux-Steiner, and K. Fostiropoulos, “On the function of a bathocuproine buffer layer in organic photovoltaic cells”, Appl. Phys. Lett. 89, 163501 (2006).
[2] J. Owen, M. S. Son, K. H. Yoo, B. D. Ahn and S. Y. Lee, “Organic photovoltaic devices with Ga-doped ZnO electrode”, Appl. Phys. Lett. 90, 033512 (2007).
[3] I. Thurzo, B. Paez, H. Mendez, R. Scholz, and D. R. T. Zahn, “Anomalous charge relaxation in channels of pentacene-based organic field-effect transistors: a charge transient spectroscopy study”, Phys. Stat. Sol. (a) 203, No.10, 2326-2340 (2006).
[4] L. Dobaczewski, A. R. Peaker, K. Bonde Nielsen, “Laplace-transform deep-level spectroscopy: The technique and its applications to the study of point defects in semiconductors”, J. Appl. Phys. 96, No.9, 4690 (2004).
[5] T.P. Nguyen, “Defect analysis in organic semiconductors”, Mat. Sci. Semicon. Proc. 9, 198-203 (2006).
[6] S. Trabattoni, S. Laera, R. Mena, A. Papagni and A. Sassella, “Preparation of highly pure quaterthiophene and role of impurities on its photoluminescence properties”, J. Mater. Chem. 14, 171-178 (2004).
[7] O. Gaudin, R. B. Jackman, T.P. Nguyen and P. Le Rendu, “Determination of traps in poly.p-phenylene vinylene. light emitting diodes by charge-based deep level transient spectroscopy”, J. Appl. Phys. 90, No.8, 4196-4204 (2001)
[8] T.P. Nguyen, P. Le Rendu, P. L_eveque, J. Ip, O. Gaudin, R.B. Jackman, “Analysis of deep traps in 4,40-bis(4-dimethylaminostyryl benzene) based light emitting diode devices”, Org. Electron. 5, 53-58 (2004).
[9] Cédric Renaud and Thien-Phap Nguyen, “Study of trap states in polyspirobifluorene based devices: Influence of aging by electrical stress”, J. Appl. Phys. 106, 053707 (2009).
[10] David E. Motaung, Gerald F. Malgas, Christopher J. Arendse, Sipho E. Mavundla, Clive J. Oliphant, Dirk Knoesen, “Thermal-induced changes on the properties of spin-coated P3HT:C60 thin films for solar cell applications”, Sol. Energ. Mat. Sol. C. 93, 1674-1680 (2009).
[11] 陳金鑫, 黃孝文, “OLED有機電激發光材料與元件”, 37.
[12] I. Thurzo, G. Pham, and D. R. T. Zahn, “A time-domain analysis of dipolar effects in copper phthalocyanine thin films on indium–tin–oxide substrates”, Semicond. Sci. Technol. 19, 1075-1080 (2004).
[13] J. W. Farmer, C. D. Lamp, and J. M. Meese, “Charge transient spectroscopy”, Appl. Phys. Lett. 41, 1063-1065 (1982).
[14] H. E. Tseng, C. Y. Liu, and S. A. Chen, “Determination of trap polarity in conjugated electroluminescent polymer by photoexcitation thermally stimulated current method”, Appl. Phys. Lett. 88, 042112 (2006).
[15] D. K. Troupis, O. Gaudin, M. D. Whitfield, and R. B. Jackman, “Ion implantation of sulphur, boron and nitrogen in diamond: a charge-based deep level transient spectroscopic investigation”, Dia. and Rela. Mater. 11, 342-346 (2002).
[16] V.I. Polyakov, A.I. Rukovishnikov, N.M. Rossukanyi, V.G. Pereverzev, “Charge-based deep level transient spectroscopy of undoped and nitrogen-doped ultrananocrystalline diamond films”, Dia. and Rela. Mater. 12, 1776–1782 (2003).
[17] D. V. Lang, “Deep-level transient spectroscopy: A new method to characterize traps in semiconductors” J. Appl. Phys., 45, No. 7, (1974).
[18] I. Thurzo, H. Méndez, and D. R. T. Zahn, “Analysis of charge transient spectroscopy data originating from Gaussian densities of electron states in organics”, phys. stat. sol. 202, No. 10, 1994–2007 (2005).
[19] I. Thurzo and K. Gmucovii, “Switching between deep-level transient spectroscopy and feedback charge capacitance modes in a versatile time-domain spectrometer”, Rev. Sci. Instrum. 65(7), 2244-2248 (1994).
[20] Yong Suk Yang, Seong Hyun Kim, Jeong-Ik Lee, Hye Yong Chu, and Lee-Mi Do, “Deep-level defect characteristics in pentacene organic thin films”, Appl. Phys. Lett. 80, No.9, 1595-1597 (2002).
[21] V.I. Polyakov, A.I. Rukovishnikov, V.P. Varnin, I.G. Teremetskaya, V.A. Laptev, “Charge-sensitive deep level transient spectroscopy of boron-doped andgamma-irradiated mono- and polycrystalline diamond”, Dia. and Rela. Mater. 12, 1783–1787 (2003).
[22] A. Klaver, V. Nádaždy, M. Zeman and R. A. C. M. M. van Swaaij, “Charge deep-level transient spectroscopy study of high-energy-electronbeam-irradiated hydrogenated amorphous silicon”, Appl. Phys. Lett. 89, 022119 (2006).

校內：2020-12-31公開
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