以電性與材料量測方法分析鈉參雜對CIGS薄膜太陽能電池的影響

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研究生：	蘇裕舜 Su, Yue-Shun
論文名稱：	以電性與材料量測方法分析鈉參雜對CIGS薄膜太陽能電池的影響 Investigation of Sodium Effects on CIGS Thin Film Solar Cells by Electrical and Material Characterization
指導教授：	賴志煌 Lai, Chih-Huang
口試委員:	甘炯耀 Gan, Jon-Yiew 洪勝富 Horng, Sheng-fu
學位類別：	碩士 Master
系所名稱：	工學院 - 材料科學工程學系 Materials Science and Engineering
論文出版年：	2013
畢業學年度：	101
語文別：	英文
論文頁數：	63
中文關鍵詞：	銅銦鎵硒、鈉效應、量測
外文關鍵詞：	CIGS, Na effect, Measurement
相關次數：	點閱：2 下載：0
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在此工作中，我們研究鈉參雜對四元靶材濺鍍之銅銦鎵硒太陽能電池的效應。ICP-MS顯示該銅銦鎵硒薄膜屬於硒缺乏的成份。電流-電壓量測顯示鈉參雜大幅提升8.2%電池效率，同時電流阻礙的現象也被解決。電容-電壓量測顯示鈉參雜使得載子濃度提升，DLCP對溫度的變化顯示在為參雜鈉的是片當中雜處了N型的較深層缺陷。最後結合Admittance量測，我們認為鈉會把氧帶到硒空缺上，進而解決了銅銦鎵硒薄膜缺硒所造成的後續問題。

Abstract
In this work, the sodium effect on Cu(In,Ga)Se2 thin films deposited by sputtering from a single quaternary target without any further post-selenization was investigated. Inductively-coupled plasma-mass spectrum (ICP-MS) shows the selenium concentration of CIGS films is 49.07%, which is selenium-poor. Current-voltage measurement (IV) shows a 8.2% efficiency enhancement from Na-free sample to Na-extra sample. In addition, the current blocking effect in Na-free sample cannot be seen in Na-extra sample. Subsequently, capacitance-voltage measurement (CV), admittance spectroscopy (AS), and drive-level capacitance profile (DLCP) were carried out to investigate sodium effects in our system. CV presents that Na incorporation can elevate free carrier density. AS combined with DLCP indicates that in Na-free sample there should be a large amount of selenium vacancies, which would be annihilated by Na incorporation. Photoluminescence measurement (PL) shows that Na incorporation introduces an additional peak, whose origin might be OSe. Based on the above information, it is plausible to take on the argument that sodium behaves as a catalyzer for oxygen atoms to neutralize selenium vacancies.
*corresponding author, Chih-Huang Lai chlai@mx.nthu.edu.tw

Table of Contents

Abstract    i
Acknowledgement    ii
List of Tables    vi
List of Figures    vii
Chapter 1 - Solar Cells    1
1.1 - PN junction    1
1.2 – The potential of CIGS solar cells    2
Chapter 2 - CIGS solar cells    4
2.1 - Typical structure of CIGS solar cells    4
2.1.1 - Soda lime glass (SLG)    5
2.1.2 - Mo electrode    6
2.1.3 - CIGS absorber    6
2.1.4 - N- type buffer layer    8
2.1.5 - Window layer (intrinsic ZnO and Al-doped ZnO)    8
2.1.6 - Anti-reflection coating    9
1.3 - The challenge of CIGS solar cells prepared by sputtering    9
2.1.8 – Intrinsic defects and Extrinsic defects of CIGS    10
2.2 – Na effects    12
2.2.1 - Electrical Effects    13
2.2.2 - Post incorporation of Na    14
2.1.7 - Sample condition of this study    14
Chapter 3 – Characterization    16
3.1 - Current-Voltage Characteristics    16
3.1.1 - Open-circuit voltage (Voc)    16
3.1.2 - Short-circuit current (Jsc)    16
3.1.3 - Max power output (Pmax)    18
3.1.4 - Fill Factor (FF)    18
3.1.5 - Dark IV    19
3.1.6 - Light IV    20
3.1.7 - Shunt resistance and ideality factor    21
3.1.8 - Electrical conductance    21
3.1.9 - Reverse saturation current (J0)    22
3.2 - Shockley Read Hall Recombination    23
3.3 - Admittance measurement    26
3.3.1 - Principle    26
3.3.2 - Experimental    29
3.3.3 - Information extracted from Admittance Measurement    29
3.3.4 - Summary of activation energies    30
3.4 - Capacitance-Voltage Measurement    32
3.5 - Drive-Level Capacitance Profiling    35
3.5.1 - Principle    35
3.5.2 – How DLCP excludes interface signal    38
3.5.3 – The origin of capacitance signal in DLCP    39
3.6 - Temperature-Dependent Open Circuit Voltage    40
3.7 - Photoluminescence    41
3.8 - External Quantum Efficiency    42
Chapter 4 - Effects of Na on CIGS thin films deposited by sputtering from a single target    43
4.1 - Experimental Detail    43
4.2 - Results and Discussion    44
4.3 - Charges near the interface region    50
4.4 - Conclusion    57
Reference    58

 
List of Tables

Table 1 The intrinsic defects and extrinsic defects of CIGS    10
Table 2 The theoretical and experimental defect levels of CIGS absorber    11
Table 3 The defect levels of CIGS absorber    11
Table 4 Summary of defect activation energies    30
Table 5 Na content from EPMA and free carrier density obtained at a limiting low temperature from DLCP.    43
Table 6 Parameters obtained from I-V measurement. The device performance is improved to a high extent. Na-free and Na-extra from the top of CIGS    45




 
List of Figures

Figure 1 The three regions in a PN junction [1]    1
Figure 2 The typical structure of CIGS solar cells    5
Figure 3 (a) CIGS chalcopyrite structure (b) The phase diagram made up of Cu2Se and In2Se3    7
Figure 4 Standard current voltage characteristics [PVCDROM]    16
Figure 5 Dark IV circuit model [from PVCDROM]    18
Figure 6 Light IV circuit model [from PVCDROM]    19
Figure 7 (a) Standard IV curve  (b) Characteristics of shunt resistance (c) Gathering series resistance and ideality factor from linear curve fitting (d) Gathering reverse saturation current and ideality factor from linear curve fitting [1]    23
Figure 8 Recombination consists of four processes 1. Electron capture 2. Electron emission 3. Hole capture 4. Hole emission; Ec(conduction band edge), Et(defect state in the bandgap), Ev(valence band edge)    23
Figure 9 A typical admittance measurement result for a CIGS solar device, in which we can see a clear step-like characteristic    27
Figure 10 Illustration of band bending caused by an AC perturbation    38
Figure 11 The I-V characteristics of the two samples. Na-free sample shows roll-over phenomenon while Na-extra sample present a normal curve.    45
Figure 12  Charge density derived from CV measurement results. Sodium may stimulate increase of charge density.    46
Figure 13 The drive-level defect density at various temperatures for Na-free sample    47
Figure 14 The drive-level defect density at various temperatures for and Na-extra (from the top) sample    47
Figure 15 The Arrhenius plot of the inflection frequencies in the admittance spectra for devices without extra sodium incorporation.    49
Figure 16 The Arrhenius plot of the inflection frequencies in the admittance spectra for devices with extra sodium incorporation from the top of CIGS.    49
Figure 17 Photoluminescence peaks indicate radiative recombination. The two samples bear different peaks, which serves as a strong evidence that the main defect in Na-free sample is VSe and that in Na-extra samples OSe.    50
Figure 18 The CV curve of Na-free sample    51
Figure 19 The CV curve of the Na-extra sample from the top of CIGS    52
Figure 20 The temperature range is where we found the defect activation energy of 392meV; we also observe a CV peak at around 0.3 to 0.4V applied DC voltage (Na-free)    53
Figure 21 The temperature range is where we found the defect activation energy of 135 meV; we also observe two CV peak at around 0.3 to 0.4V and 0.8V applied DC voltage (Na-extra from the top of CIGS)    53
Figure 22 IVT for the device without extra sodium incorporation  (Recombination activation energy= 0.55eV)    54
Figure 23 IVT for the device with extra sodium incorporation from the top of CIGS (Recombination activation energy= 0.80eV)    55
Figure 24 The sample without extra –sodium incorporation presents a poorer QE performance over the whole spectrum    56
Figure 25 The sample with extra –sodium incorporation from the top of CIGS presents a better QE performance over the whole spectrum; that is, QE of all wavelengths are improved    56


                                

Reference

1. Edited by Daniel Abou-Ras, T.K., and Uwe Rau, Advanced Characterization Techniques for Thin Film Solar Cells.
2. Kronik L, C.D., Schock H W, , Adv. Mater., 1998. 10 (1): p. 31.
3. Ishizuka, S.Y., A.; Islam, M. M.; Shibata, H.; Fons, P.; Sakurai, T.; Akimoto, K.; Niki, S., J. Appl. Phys. , 2009. 106 (3), 6.
4. Contreras, M.A.T., J.; Gabor, A.; Tennant, A.; Ramanathan, K.; Asher, S.; Franz, A.; Keane, J.; Wang, L.; Noufi, R.,, Sol. Energy Mater. Sol. Cells 1996, . 41-2, : p. 231-246.
5. Schlenker, T.L., V.; Schock, H. W.; Werner, J. H., , Thin Solid Films 2005, . 480, (29-32).
6. Contreras, M.A.E., B.; King, D.; Swartzlander, A.; Dullweber, T.,, Thin Solid Films, 2000,. 361, : p. 167-171.
7. Contreras, M.A., . PROGRESS IN PHOTOVOLTAICS: RESEARCH AND APPLICATIONS, 1999, . 7,( 6).
8. Park, J.S.D., Z.; Kim, S.; Perepezko, J. H.,, J. Appl. Phys. , 2000, . 87 (8 ): p. 3683-3690.
9. Canava, B.G., J. F.; Vigneron, J.; Lincot, D.; Etcheberry, A. In Chemical elaboration of well defined Cu(In,Ga)Se2 surfaces after aqueous oxidation etching. Pergamon-Elsevier Science Ltd, 2003: p. 1791-1796.
10. Darga, A.M., D.; Djebbour, Z.; Dubois, A. M.; Guillemoles, J. F.; Connolly, J. P.; Roussel, O.; Lincot, D.; Canava, B.; Etcheberry, A., Two step wet surface treatment influence on the electronic properties of Cu(In,Ga)Se2 solar cells Elsevier Science Sa: p. 2550-2553.
11. Wei, S.H.Z., S. B.; Zunger, A., , Appl. Phys. Lett., 1998,. 72(24 ): p. 3199-3201.
12. DS, A., MATER RES SOC S P, 1991,. 228(267).
13. Wei, S.H.Z., A., , J. Appl. Phys. , 1995, . 78 (6): p. 3846-3856.
14. Zhang, S.B., et al.,, Defect physics of the CuInSe_ {2} chalcopyrite semiconductor. . Physical Review B, 1998. 57((16)): p. p. 9642.
15. N. Kohara, T.N., M. Nishitani, Y. Hashimoto, T. Wada, Appl. Phys. Lett. , 1997, . 71(835).
16. al, C.-H.C.e., One-step fabrication of chalcopyrite phase Cu(In,Ga)Se2 absorber layer by sputtering without post-selenization.
17. M. A. Contreras, B.E., P. Dippo, J. Webb, J. Granata, K. Ramanathan, S. Asher, A. Swartzlander, and R. Noufi 26th IEEE Photovoltaic Specialists Conference (IEEE, New York, 1997), 1997: p. p. 359.
18. M. Ruckh, D.S., M. Kaiser, R. Schaffler, T. Walter, and H. W. Schock,, World Conference on Photovoltaic Energy Conversion 1994, IEEE: New York. p. 156.
19. <Thesis_The Effect of Trapping Defects on CIGS Solar-Cell Performance.pdf>.
20. P. K. Johnson1, J.T.H., J. D. Cohen, K. Ramanathan and J. R. Sites, A Comparative Study of Defect States in Evaporated and Selenized CIGS(S) Solar Cells. PROGRESS IN PHOTOVOLTAICS: RESEARCH AND APPLICATIONS, 2005.
21. Lei, B., et al., Cadmium ion soaking treatment for solution processed CuInSxSe2−x solar cells and its effect on defect properties. Solar Energy Materials and Solar Cells, 2011. 95(8): p. 2384-2389.
22. Tobias Eisenbarth, R.C., Christian A. Kaufmann, Axel Eicke and Thomas Unold, Influence of iron on defect concentrations and device performance for Cu(In,Ga)Se2 solar cells on stainless steel substrates. PROGRESS IN PHOTOVOLTAICS: RESEARCH AND APPLICATIONS, 2012.
23. Tobias E., e.a., Characterization of metastabilities in Cu(In,Ga)Se2 thin-film solar cells by capacitance and current-voltage spectroscopy. J. Appl. Phys., 2011.
24. Tobias Eisenbarth, T.U., Raquel Caballero, Christian A. Kaufmann, and Hans-Werner Schock, Interpretation of admittance, capacitance-voltage, and current-voltage signatures in Cu(In,Ga)Se2 thin film solar cells. J. Appl. Phys., 2010. 107,.
25. BAYHAN, H., Determination of Defect Distribution in a Ga-rich ZnO/CdS/Cu(In,Ga)Se2 Solar Cell by Admittance Spectroscopy, 2003.
26. Jüri Krustok*, M.D., Andri Jagomägi, Maarja Grossberg, and Jaan Raudoja, Device characteristics of CuInSe2-based solar cells.
27. Todorov, T.K., et al., Solution-processed Cu(In,Ga)(S,Se)2absorber yielding a 15.2% efficient solar cell. Progress in Photovoltaics: Research and Applications, 2013. 21(1): p. 82-87.
28. Erslev, P.T., W.N. Shafarman, and J.D. Cohen, Metastable properties of Cu(In[sub 1−x]Ga[sub x])Se[sub 2] with and without sodium. Applied Physics Letters, 2011. 98(6): p. 062105.
29. Cao, Q., et al., Defects in Cu(In,Ga)Se2 Chalcopyrite Semiconductors: A Comparative Study of Material Properties, Defect States, and Photovoltaic Performance. Advanced Energy Materials, 2011. 1(5): p. 845-853.
30. M. Igalsona, M.W., J. Wennerbergb, The change of the electronic properties of CIGS devices induced by the damp heat treatment. Thin Solid Films 2002. 403 –404: p. 320–324.
31. M. Schmidt, D.B., R. Schaffler, H.W. Schock, U. Rau, Infuence of damp heat on the electrical properties of Cu(In,Ga)Se2 solar cells. Thin Solid Films 2000. 361-362: p. 283-287.
32. J.P.Connolly, Z.D., A.Darga, C.Bazin, D. Mencaraglia, M. Benosman, N.Bodereau, and D.L. JF Guillemoles, J. Kessler, N. Naghavi, J. Kurdi, O. Kerrec, ANALYSIS OF EFFICIENCY LIMITING PROCESSES IN THIN FILM Cu(In,Ga)(S,Se)2 ELECTRODEPOSITED SOLAR CELLS.
33. Heath, J.T., Bulk and metastable defects in CuIn1−xGaxSe2 thin films using drive-level capacitance profiling. Journal of Applied Physics, 2004. 95(3): p. 1000.
34. Michelson, C.E., A.V. Gelatos, and J.D. Cohen, Drive-level capacitance profiling: Its application to determining gap state densities in hydrogenated amorphous silicon films. Applied Physics Letters, 1985. 47(4): p. 412.
35. C. P. Thompson, S.H., W. Shafarman, D. Desai,, IEEE Photovoltaic Specialists Conference 33rd,, 2008: p. p1-6.
36. U. Rau, H.W.S., Electronic properties of Cu(In,Ga)Se2 heterojunction solar cells-recent achievements, current understanding, and future challenges. Appl. Phys. , 1999. 69(131).
37. V. Nadenau, U.R., A Jasenek, and H.W. Shock, , Electronic properties of CuGaSe2-based heterojunction solar cells. Part I. Transport analysis Appl. Phys. , 2000. 87: p. 584

38. M. Turcu, O.P., and U. Rau, Interdependence of absorber composition and recombination mechanism in Cu(In,Ga)(Se,S)2 heterojunction solar cells. Appl. Phys, 2002. 80 p. p. 2598.
39. J.E. Phillips, e.a., Polycrystalline Heterojunction Solar Cells: A Device Perspective. Phys. Stat. Sol 1996. 194: p. 31.
40. S. S. Hegedus and W. N. Shafarman, T.-F.S.C.D.M.a.A., ” Prog. Photovolt: Res. Appl. 12, pp.155-176, 2004., Thin-Film Solar Cells: Device Measurements and Analysis. Prog. Photovolt: Res. Appl. , 2004. 12: p. pp.155-176.
41. N Rega, S.S., J. Albert, S. Nishiwaki, A. Najogin, M.Ch. Lux-Steiner, R. Kniese, and M.J. Romero Thin Solid Film 2005. 480-481: p. 286-290.
42. G. Dagan, F.A.-E., D. J. Dunlavy, R. J. Matson, D. Cahen, Chem. Mater. , 1990,. 2(286).
43. D. Cahen, i.T.a.M.C., Proc. 7th Int. Conf. (Eds: S. K. Deb, A. Zunger), , Materials Research Society, Pittsburgh, , 1987. Vol. TMC: p. 433-442.
44. J.T. Heath, J.D. Cohen, W.N. Shafarman Thin Solid Films 2003.
45. Leeor Kronik, D.C., and Hans Werner Schock, Effects of Sodium on PolycrystallineCu(In,Ga)Se2 and Its Solar Cell Performance. Adv. Mater, 1998. 10(No. 1).

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