臺灣博碩士論文加值系統

薄膜太陽能電池材料種類涵蓋甚廣，其中以矽基(Si-based)及銅銦鎵硒(Cu(In,Ga)Se2,CIGS)兩種，被視為最具商品化發展潛力。相關製程研究之最終目的就是開發低耗損、低成本製程，製造高效率、大面積與可撓性的薄膜太陽能電池。在薄膜太陽能電池結構中，使用n-ZnO透明導電薄膜(Transparent conductive oxide, TCO)作為窗口層，於提昇太陽能電池效率上，扮演重要的角色。
本研究以脈衝濺鍍法(Pulsed DC magnetron sputtering)成長ZnO:Ga(GZO)透明導電薄膜。針對製程參數的控制與後熱處理的改善，探討薄膜微結構、光電特性及其於太陽光電的應用方面。研究中以GZO薄膜作為透明電極，分別進行濕熱穩定性及表面粗化特性探討。針對CIGS薄膜太陽能電池材料，我們亦提出一種創新成長(Cu(In,Ga)(Se,S)2,CIGSS)薄膜吸收層的技術，並藉由鍍膜參數調整與後退火處理程序，獲得具黃銅礦結構之薄膜吸收層，探討此吸收層薄膜之微結構、組成及其光電性質之關連。
GZO透明導電薄膜研究結果顯示：於脈衝頻率10kHz及膜厚500nm下，可得最低電阻率, 2.01×10-4Ω-cm與可見光穿透率, 86％及光學能隙, 3.83eV。由鍍膜之後退火處理研究得知：經300℃氬氣中退火處理後，薄膜電阻率下降，且其紅外線穿透率低於5%(λ=1400nm) ，而其反射率高於70%(λ=2400 nm)。透過濕熱穩定性及表面粗化研究得知：GZO薄膜之濕熱穩定性較AZO薄膜高。兩者皆可應用於薄膜太陽能電池前電極或上電極。
CIGS薄膜太陽能電池吸收層研究顯示：本實驗室開發之新穎製程所得之CIGSS薄膜，具有單一的黃銅礦相態且其結晶性良好。電性分析結果得知此CIGSS吸收層電阻值為45 Ωcm、載子濃度為4.86×1016 cm-3，薄膜光學能隙值估計為1.18eV左右。上述光電特性滿足目前開發中之CIGS薄膜太陽能電池吸收層之要求。

Thin film solar cells have attracted lots of attention in which many researching works had been devoted. Among which, the Si-based and Cu(In,Ga)Se2 thin film solar cells are regarded as two of the most potential technologies for further commercialization. Accordingly, researchers are now focusing on the preparation of high efficiency, large area with low cost and wastage process for the flexible thin film solar cells.
Traditionally, n-type transparent conductive oxides were adapted as the window layers which play an important role in the fabrication of thin film solar cells. Accordingly, in the study a ZnO:Ga thin film was prepared by pulsed DC magnetron sputtering to further improve the conversion efficiency and performance of thin film solar cells. By optimal deposition parameters and post-annealing treatment, the relationship of thin film microstructure and the corresponding optoelectronic properties were thoroughly investigated. To evaluate the applicability for solar energy materials, the deposited transparent GZO and AZO films were further underwent the damp heat treatment and surface texturing experiments.
The results show that the GZO thin film has a lowest resistivity of 2.01×10-4Ω-cm and with an optical transmittance over 86% and Eopt. of 3.83eV for films deposited at pulse frequency of 10kHZ with 500nm in thickness. After post-annealing treating at 300oC under argon atmosphere, the resistivity of GZO thin films were further decreased with an IR transmittance (λ= 1400 nm) lower than 5% and optical reflectance (λ= 2400 nm) higher than 70%, respectively. According to the results of damp heat stability treatment and surface texturing experiment, the GZO films are more robust and endurable for the environmental impact in comparison to those for AZO thin films as the front contacts or top electrodes of thin film solar cells.
In addition, a novel sputtering process has been proposed to prepare the Cu(In,Ga)(Se,S)2 absorber with chalcopyrite structure by delicately controlling the sputtering parameters and employing the post-annealing treatment. Finally, the influence of the microstructures and the film compositions on the optoelectronic properties of CIGSS absorber was extensively investigated.
The prepared CIGSS thin film has a chalcopyrite structure and improved crystallinity which has a resistivity of 45 Ωcm and carrier concentration of 4.86×1016 cm-3 with an optical band gap estimated to be around 1.18eV. These properties have shown to be satisfactory for the ideal CIGS thin film solar cells.

Contents
Contents..................................................Ⅰ
Abstract (in Chinese).....................................Ⅲ
Abstract (in English).....................................Ⅳ
Acknowledgements (in Chinese).............................Ⅵ
Table captions............................................Ⅷ
Figure captions...........................................Ⅸ
Notations...............................................ⅩⅢ

Chapter 1 Introduction.....................................1
1.1 Background.............................................1
1.2 Motivation and objective...............................3

Chapter 2 Literature review................................6
2.1 Structure and properties of Gallium-doped ZnO (GZO)....6
2.2 Transparent conducting oxide for thin-film solar cells.8
2.3 Cu(In,Ga)Se2 absorber layer...........................10
2.4 Cu(In,Ga)Se2 deposition processes.....................12
2.5 Device structure......................................16

Chapter 3 Experimental procedure..........................18
3.1 Introduction..........................................18
3.2 Experimental equipment................................18
3.3 Thin film growth processes............................19
3.4 Characterization Techniques...........................24
3.4.1 Structural analysis.................................24
3.4.2 Compositional analysis..............................25
3.4.3 Optical analysis....................................26
3.4.4 Electrical analysis.................................27

Chapter 4 Results and discussions.........................29
4.1. Growth and characteristics of GZO thin films.........29
4.2. Effect of post-annealing on the properties of GZO thin films.....................................................39
4.3. Damp heat stability on the properties of AZO and GZO thin films................................................48
4.4. Surface textured on the properties of AZO and GZO thin films.....................................................53
4.5. Growth and characteristics of CIGSS thin films.......61
4.5.1 Effects of substrate temperature on the compositional and structural properties of CIGSS precursor films........61
4.5.2 Effects of post annealing temperature on CIGSS film properties................................................63
4.5.3 Effects of post annealing on CIGSS film properties..73

Chapter 5 Conclusions and outlooks........................81

References................................................83

Publications list.........................................93

Table captions
Table 2.1 Fundamental properties of ZnO………………………… 7
Table 4.1 Dependence of the composition determined by EDS for CIGSS films deposited at different substrate temperatures………………………62
Table 4.2 EDS data of as-deposited and CIGSS films annealed at different temperatures………………………………………………65
Table 4.3 EDS analysis of CIGSS films annealed at 490 ℃ for different times………………………………………74

Figure captions
Figure 2.1 Crystal structure of the zinc oxide (ZnO)……6
Figure 2.2 (a) Zinc blende ZnSe lattice and (b) chalcopyrite unit cell for CuInSe2.[49]…………10
Figure 2.3 Pseudobinary cut Cu2Se-In2Se3 of the ternary phase diagram. [48]……….. 11
Figure 2.4 Schematic co-evaporation process…………………. 13
Figure 2.5 Schematic of NREL three stage process…………… 14
Figure 2.6 Schematic selenization process used H2Se to selenize a metal stack precursors……………………………………15
Figure 2.7 Structure of a CIGS thin-film solar cell and issues to improve the efficiency. [69] ………………………17
Figure 3.1 The flow chart of the experiment…………………… 20
Figure 3.2 Schematic representations of (a) magnetron sputtering and (b) hybrid sputtering system……………………21
Figure 3.3 Schematic representation of the heat-treatment system……………………. 21
Figure 3.4 Schematic representation of the Damp heat system……………………….. 22
Figure 4.1 Deposition rate of GZO films prepared at various pulse frequencies……… 29
Figure 4.2 XRD patterns of GZO films prepared at various pulse frequencies……….. 30
Figure 4.3 The crystallite size and the FWHM of GZO films prepared at various pulse frequencies………………………………31
Figure 4.4 AFM image of GZO films as a function of pulse frequencies: (a) 10kHz,(b) 30kHz, (c)50kHz………………………31
Figure 4.5 (a) Surface morphology and (b) cross section of GZO film prepared at a pulse frequency of 10 kHz, with a thickness of 500nm……………………32
Figure 4.6 Resistivity, carrier concentration and Hall mobility of GZO films prepared at various pulse frequencies……………………………………………33
Figure 4.7 Optical transmittance spectra of GZO films prepared at various pulse frequencies………………………………34
Figure 4.8 XRD and FWHM patterns of GZO films prepared at a pulse frequency of 10 kHz with various thicknesses…………35
Figure 4.9 The RMS surface roughness of GZO films prepared at a pulse frequency of 10 kHz with various thicknesses…35
Figure 4.10 Resistivity, carrier concentration and Hall mobility of GZO films prepared at a pulse frequency of 10 kHz with various film thickness………………………………………36
Figure 4.11 Optical transmittance spectra of GZO films prepared at a pulse frequency of 10 kHz with various thicknesses………………………………………..37
Figure 4.12 Optical band gap of GZO films prepared at a pulse frequency of 10 kHz with various thicknesses…………38
Figure 4.13 XRD patterns, FWHM and Crystallite-size of GZO films prepared under various annealing temperatures…………40
Figure 4.14 Resistivity, carrier concentration and Hall mobility of GZO films prepared under various annealing temperatures……………………………………………………………………41
Figure 4.15 XPS spectra of GZO thin film as a function of annealed temperature……………………………………………………… 42
Figure 4.16 The change of O1s as a function of annealing temperature…………………………………………………………………… 43
Figure 4.17 Optical transmittance of GZO films prepared under various annealing temperatures………………………………44
Figure 4.18 Optical band gap of GZO films prepared under various annealing temperatures…………………………………………44
Figure 4.19 Infrared reflectance and transmittance of GZO films prepared under various annealing temperatures…………46
Figure 4.20 Photoluminescence of GZO films prepared under various annealing temperatures…………………………………………47
Figure 4.21 XRD patterns of (a) AZO and (b) GZO films at different time of damp heat treatment………………………………48
Figure 4.22 SEM micrographs for the samples of AZO films :(a) as-deposited (b) after damp heat 999h, and for GZO films :(c) as-deposited (d) after damp heat 999h……………49
Figure 4.23 (a) AZO and (b) GZO films versus each resistivity, carrier concentration and Hall mobility at different time of damp heat treatment……………………………50
Figure 4.24 The changes of O1s in the (a) AZO and (b) GZO films at different time of damp heat treatment………………51
Figure 4.25 (a) AZO and (b) GZO films versus each optical transmittance spectra at different time of damp heat treatment.………………………………………………………………………52
Figure 4.26 SEM micrographs of textured AZO films as function of etch time in 0.5% HCl(aq.) (a) as-deposition; (b) etched for 15 seconds; (c) etched for 30 seconds and (d) etched for 45 seconds………………………………………………54
Figure 4.27 SEM micrographs of textured GZO films as function of etch time in 0.5% HCl(aq.) (a) as-deposition; (b) etched for 15 seconds; (c) etched for 30 seconds, and (d) etched for 45 seconds………………………………………………54
Figure 4.28 Electrical properties of (a) AZO films; and (b) GZO films as function of etching time in 0.5% HClaq………56
Figure 4.29 XRD patterns of (a) AZO films; (b) GZO films as function of etching time in 0.5% HClaq……………………………57
Figure 4.30 Transmittance spectra of (a) AZO and (b) GZO thin films as function of etching time in 0.5% HClaq………59
Figure 4.31 Optical properties of (a) AZO and (b) GZO thin films as function of etching time in 0.5% HClaq………………60
Figure 4.32 XRD diffraction patterns of CIGSS films deposited at different substrate temperatures…………………61
Figure 4.33 Surface morphologies of CIGSS thin films deposited at different substrate temperatures of (a) RT, (b) 150℃, (c) 200℃, (d) 250℃………………………………………63
Figure 4.34 X-ray diffraction patterns of CIGSS films before and after annealing at different temperature…………64
Figure 4.35 Dependence of the composition determined by DES for CIGSS films at different annealing temperatures…………65
Figure 4.36 SIMS depth profile of an as-deposited CIGSS films (a) and one annealed at 490℃ (b)……………………………67
Figure 4.37 SEM morphologies of CIGSS films annealed at different temperatures: (a) as-deposited, (b) 460℃, (c) 490℃, (d) 520℃, (e) 550℃, (f) 580℃………………………………69
Figure 4.38 AFM micrograph of CIGSS films annealed at different temperatures: (a) as-deposited, (b) 460℃, (c) 490℃, (d) 520℃, (e) 550℃, (f) 580℃………………………………70
Figure 4.39 Transmittance plots of CIGSS films as a function of annealing temperature……………………………………71
Figure 4.40 Plot of (αhν)2 versus photon energy for CIGSS films as a function of annealing temperature……………………72
Figure 4.41 Resistivity, Hall mobility, and carrier concentration of CIGSS films as a function of annealing temperature……………………………………………………………………72
Figure 4.42 X-ray diffraction patterns of CIGSS films annealed at 490℃ for different times………………………………73
Figure 4.43 SIMS depth profile of CIGSS films deposited at 150℃ (a) and annealed at 490℃ for 5 minutes (b)……………76
Figure 4.44 SEM morphologies of CIGSS films annealed at 490℃ for different times:(a) 5 minutes, (b) 15 minutes, (c) 25 minutes…………………………………………………………………77
Figure 4.45 Transmittance plots of CIGSS films annealed at 490℃ for different times…………………………………………………77
Figure 4.46 Plot of (αhν)2 versus photon energy for CIGSS films annealed at 490℃ for different times……………………78
Figure 4.47 Resistivity, carrier concentration and Hall mobility of CIGSS films annealed at 490℃ for different times………………………………………………………………………………79

References
[1]K. Badeker,“Concerning the electricity conductibility and the thermoelectric energy of several heavy metal bonds", Annalen der Physik (Leipzig) 22 (1907) 749-766.
[2]K. L. Chopra, S. Major and D. K. Pandya, “Transparent conductors-A Status Review", Thin Solid Films 102 (1983) 1-46.
[3]T. Minami,“Transparent conducting oxide semiconductors for transparent electrodes”, Semiconductor Science and Technology 20 (2005) S35-S44.
[4]Y. C. Lin, J. Y. Li, and W. T. Yen, “Low temperature deposition of ITO thin film on PES substrate using pulse magnetron sputtering”, Applied Surface Science 254 (2008) 3262-3268.
[5]Y. C. Lin, S. J. Chang, Y. K. Su, T. Y. Tasi, C. S. Chang, S. C. Shei, C. W. Kuo, S.C. Chen, “InGaN/GaN light emitting diodes with Ni/Au, Ni/ITO and ITO p-type contacts”, Solid state Electronics 47 (2003) 849-853.
[6]Claes G. Granqvist,“Transparent conductors as solar energy materials: a panoramic review”, Solar Energy Materials and Solar Cells 91 (2007) 1529-1598.
[7]T. Minami,“Present Status of Transparent Conducting Oxide Thin-Film development for indium-tin-oxide (ITO) Substitutes”, Thin Solid Films 516 (2008) 5822-5828.
[8]K. Ellmer, A. Klein, B. Rech, Transparent conductive zinc oxide, Springer, 2007.
[9]S. Major, S. Kumar, M. Bhatnagar and K. L.
Chopra,“Effect of hydrogen plasma treatment on transparent conducting oxides”, Applied Physics Letters 49 (1986) 394-396.
[10]T. Minami, H. Sata, H. Nanto and S. Takata,“Electrical and optical properties of zinc oxide thin films prepared by rf magnetron sputtering for transparent electrode applications”, Japanese Journal of Applied Physics 24 (1985) L781-L784.
[11]J. Wienke, B. van der Zanden , M. Tijssen, M. Zeman,“Performance of spray-deposited ZnO:In layers as front electrodes in thin-film silicon solar cells”, Solar Energy Materials and Solar Cells 92 (2008) 884-890.
[12]V. Assuncao, Elvira Fortunato, Antonio Marques, Alexandra Goncalves, Isabel Ferreira, Hugo Aguas, Rodrigo Martins,“New challenges on gallium-doped zinc oxide films prepared by r.f. magnetron sputtering”, Thin Solid Film 442 (2003) 102-106.
[13]A. David, J. Glocker, “Influence of the plasma on substrate heating during low‐frequency reactive sputtering of AIN”, The Journal of Vacuum Science and Technology A 11 (1993) 2989-2993.
[14]P. Frach, D. Glöß, K. Goedicke, M. Fahland and W. -M. Gnehr,“High rate deposition of insulating TiO2 and conducting ITO films for optical and display applications ”, Thin Solid Films 445 (2003) 251-258.
[15]S. Mayer, K.L.Chopra, “Indium-doped zinc oxide films as transparent electrodes for solar cells”, Solar Energy and Materials 17 (1988) 319-327.
[16]H. N. Wanka, E. Lotter and M. B. Shubert, in Amorphous Silicon Technology-1994, edited by E. A. Shiff, M. Hack, A. Madan, M. Powell and A. Matsuda (Mater. Res. Soc. Symp . Proc. 336, Pittburgh, 1994) p.657.
[17]J. R. Tuttle, J. S. Ward, A. Duda, T. A. Berens,M. A. Contreras, K. R. Ramanathan, A. L. Tennant,J. Keane, E. D. Cole, K. Emery, and R. Noufi, “The pperformance of CIGS-based solar cells in conventional and concentrator applications”, Materials Research Society 426 (1996) 143-151.
[18]I. Repinsl, M.A. Contreras, B. Egaas, C. DeHart, J. Scharf, C.L. Perkins, B. To and R. Noufi, “19.9%-Efficient ZnO/CdS/CuInGaSe2 solar cell with 81.2% fill factor”, Progress in Photovoltaics: Research and Applications 16 (2008) 235-239.
[19]M.A. Green, K. Emery, Y. Hishikawa, W. Warta, “Solar cell efficiency tables”, Progress in Photovoltaics: Research and Applications, 16 (2008) 435-440.
[20]X. Wu, J.C. Keane, R.G. Dhere, C. DeHart, A. Duda, T.A. Gessert, S. Asher, D.H. Levi, P. Sheldon, “16.5% efficient CdS/CdTe polycrystalline thin film solar cell”, Conference Procedure 17th European Conference Photovoltaic Solar Energy Conference, Munich. October 22 (2001) 955-999.
[21]M. Yoshimi, T. Sasaki, T. Sawada, T. Suezaki, T. Meguro, T. Matsuda, K. Santo, K. Wadano, M.I chikawa, A. Nakajima, K. Yamamoto, “High efficiency thin film silicon hybrid solar cell module on 1m/sup2/-class large area substrate” Conference Record, 3rd World Conference on Photovoltaic Energy Conversion, Osaka, May, (2003) 1566-1569.
[22]Hyungduk Koa, Weon-Pil Taib, Ki-Chul Kimc, Sang-Hyeob Kimc, Su-Jeong Suha, Young-Sung Kima, “Growth of Al-doped ZnO thin films by pulsed DC magnetron sputtering”, Journal of Crystal Growth 277 (2005) 352-358.
[23]Keunbin Yim, Chongmu Lee, “Dependence of the electrical and optical properties of sputter-deposited ZnO:Ga films on the annealing temperature,time, and atmosphere”, Journal of Materials Science: Materials in Electronics 18 (2007) 385-390.
[24]B. Rech, H. Wagner, “B. Rech, H. Wagner, “Potential of amorphous silicon for solar cells”, Journal of Applied Physics A 69 (1999) 155-167.
[25]U. Rau, H.W. Schock, “Electronic properties of Cu(In,Ga)Se2 heterojunction solar cells-recent achievements, current understanding, and future challenges”, Journal of Applied Physics A 69 (1999) 131-147.
[26]T. Tohsophon, J. Hupkes, S. Calnan, W. Reetz, B. Rech, W. Beyer, N. Sirikulrat, “Damp heat stability and annealing behavior of aluminum doped zinc oxide films prepared by magnetron sputtering”, Thin Solid Films 511-512 (2006) 673-677.
[27]T. Tohsophon, J. Hüpkes, H. Siekmann, B. Rech, M. Schultheis, N. Sirikulrat, “High rate direct current magnetron sputtered and texture-etched zinc oxide films for silicon thin film solar cells”, Thin Solid Films 516 (2008) 4628-4632.
[28]W. Gopel, U. Lampe, “Influence of defects on the electronic structure of zinc oxide surfaces”, Physical Review B 22 (1980) 6447-6462.
[29]C. Agashe, O. Kluth, J. Hupkes, U. Zastrow, B. Rech,“Carrier concentration dependence of band gap shift in n- type ZnO:Al films”, Journal of Applied Physics 101 (2007) 083705-083705-7.
[30]Quan-Bao Ma, Zhi-Zhen Ye, Hai-Ping He, Li-Ping Zhu, Jing-Rui Wang, Bing-Hui Zhao, “Influence of Ar/O2 ratio on the properties of transparent conductive ZnO: Ga films prepared by DC reactive magnetron sputtering”, Materials Letters 61 (2007) 2460-2463.
[31]Z.Z. Ye, J.F. Tang, Applied Optics. 28 (1989) 2817.
[32]K. Ellmer, A. Klein, B. Rech, “Transparent Conductive Zinc Oxide: Basics and Applications in Thin Film Solar Cells”, Springer, illustrated edition edition (2007) p6.
[33]Y. Kashiwaba, K. Sugawara, K. Haga, H. Watanabe, B.P. Zhang, Y. Segawa, “Characteristics of c-axis oriented large grain ZnO films prepared by low-pressure MO-CVD method”, Thin Solid Films 411 (2002) 87-90.
[34]K.T.R. Reddy, T.B.S. Reddy, I. Forbes, R.W. Miles,“Highly oriented and conducting ZnO:Ga layers grown by chemical spray pyrolysis ”, Surface and Coatings Technology 151-152 (2002) 110-113.
[35]R.A. Asmar, S. Juillaguet, M. Ramonda, A. Giani, P. Combette, A.Khoury, A. Fourcaran, “Fabrication and characterization of high quality undoped and Ga2O3-doped ZnO thin films by reactive electron beam co-evaporation technique”, Journal of Crystal Growth 275 (2005) 512-520.
[36]A. Suzuki, T. Matsushita, T. Aoki, Y. Yoneyama, M. Okuda,“Micro-Textured Milky ZnO:Ga Thin Films Fabricated by Pulsed Laser Deposition Using Second-Harmonic-Generation of Nd:YAG Laser”, Japanese Journal of Applied Physics 38 (1999) L71-L73.
[37]H. Hirasawa, M. Yoshida, S. Nakamura, Y. Suzuki, S. Okada, K. Kondo, “ZnO:Ga conducting-films grown by DC arc-discharge ionplating”, Solar Energy Materials and Solar Cells 67 (2001) 231-236.
[38]B. Sang, K. Kushiya, D. Okumura, O. Yamase,“Performance improvement of CIGS-based modules by depositing high-quality Ga-doped ZnO windows with magnetron sputtering”, Solar Energy Materials and Solar Cells 67 (2001) 237-245.
[39]H. Ko, W. P. Tai, K. C. Kim, S. H. Kim, S. J. Suh, Y. S. Kim,“Growth of Al-doped ZnO thin films by pulsed DC magnetron sputtering”, Journal of Crystal Growth 277 (2005) 352-358.
[40]N. R. Aghamalyan, E. A. Kafadaryan, R. K. Hovsepyan, S. I. Petrosyan, “Absorption and reflection analysis of transparent conductive Ga-doped ZnO films”, Semiconductor science and technology 20 (2005) 80-85.
[41]B.T. Lee, T. H. Kim, S.H. Jeong, “Growth and characterization of single crystalline Ga-doped ZnO films using rf magnetron sputtering”, Journal of Physics D: Applied Physics 39 (2006) 957-961.
[42]Q.B. Ma, Z.Z. Ye, H.P. He, L.P. Zhu, J.Y. Huang, Y.Z. Zhang, B.H. Zhao, “Influence of annealing temperature on the properties of transparent conductive and near-infrared reflective ZnO:Ga films”, Scripta Materialia 58 (2008) 21-24.
[43]O. Klutha, B. Rech, L. Houben, S. Wieder, G. Schope, C. Beneking, H. Wagner, A. Loffl, H.W. Schock, “Texture etched ZnO:Al coated glass substrates for silicon based thin film solar cells”, Thin Solid Films 351 (1999) 247-251.
[44]F.J. Pern, R. Noufi, X. Li, C. DeHart, and B. To,“Damp-Heat Induced Degradation of Transparent Conducting Oxides for Thin-Film Solar Cells”, Presented at the 33rd IEEE Photovoltaic Specialists Conference San Diego, California May 11-16 (2008).
[45]R. Groenen, J. L. Linden, H. R. M. van Lierop, D. C. Schram, A. D. Kuypers, M. C. M. van de Sanden, “An expanding thermal plasma for deposition of surface textured ZnO:Al with focus on thin film solar cell applications”, Applied Surface Science 17 (2001) 40-43.
[46]Katsumi Kushiya, Baosheng Sang, Daisuke Okumura, and Osamu Yamase, “Application of Stacked ZnO Films as aWindow Layer to Cu(InGa)Se2-Based Thin-Film Modules”, Japanses Journal of Applied Physics 38 (1999) 3997-4001.
[47]E. B. Yousfi, B. Weinberger, F. Donsanti, P. Cowache, D. Lincot, “Atomic layer deposition of zinc oxide and indium sulfide layers for Cu(In,Ga)Se2 thin-film solar cells”, Thin Solid Films 387 (2001) 29-32.
[48]M.L. Fearheiley, “The phase relations in the Cu, In, Se system and the growth of CuInSe2 single crystals”, Solar Cells 16 (1986) 91-100.
[49]T. Markvart and L. Castaner,“Solar cells :materials, manufacture and operation”, Oxford :Elsevier Advanced Technology, (c2005).
[50]A. Rockettr, F. Abou-Elfotouh, D. Albin, “Structure and chemistry of CuInSe2 for solar cell technology: current understanding and recommendations”, Thin Solid Films 237 (1994) 456-461.
[51]Wei S H, Zunger A. “Band offsets and optical bowings of chalcopyrites and Zn-based II-VI alloys”, Journal of Applied Physics 78 (1995) 38-46.
[52]J.E Jaffe and A. Zunger.“Theory of the band-gap anomaly in ABC2 chalcopyrite semiconductors”, Physical Review B 29 (1984) 1882 -1903.
[53]T. Negami, Y. Hashimoto, S. Nishiwaki, “Cu(In,Ga)Se2 thin-film solar cells with an efficiency of 18%”, Solar Energy Materials and Solar Cells 67 (2001) 331-335.
[54]R. Cayzac, F. Boulc’h, M. Bendahan, P. Lauque, P. Knauth,“Direct preparation of crystalline CuInS2 thin films by radiofrequency sputtering”, Materials Science and Engineering B 157 (2009) 66-71.
[55]Tsuyoshi Ohashi, Masaki Wakamori, Yoshio Hashimoto, Kentaro Ito, “Cu(In1-xGax)S2 Thin Films Prepared by Sulfurization of Precursors Consisting of Metallic and Gallium Sulfide Layers”, Japanese Journal of Applied Physics 37(1998) 6530-6534.
[56]M. Marudachalam, H. Hichri, R. Klenk, R. W. Birkmire, W. N. Shafarman and J. M. Schultz, “Preparation of Homogeneous Cu(InGa)Se2 Films by Selenization of Metal Precursors in H2Se Atmosphere”, Applied Physics Letters 67 (1995) 3978-3980.
[57]F. O. Adurodija, S. K. Kim, S. D. Kim, J. S. Song, K. H. Yoon, and B. T. Ahn, “Characterization of co-sputtered Cu-In alloy precursors for CuInSe2 thin films fabrication by close-spaced selenization”, Solar Energy Materials and Solar Cells 55 (1998) 225-236.
[58]C.D. Lokhande, “Pulse Plated Electrodeposition of CuInSe2 Films”, Journal of Electrochemical society 134 (1987) 1727-1729.
[59]F.J. Pern, R. Noufi, A. Mason and A. Franz,“Characterizations of electrodeposited CuInSe2 thin films: Structure, deposition and formation, mechanisms”, Thin Solid Films 202 (1991) 299-314.
[60]Se Jin Ahn, Chae Woong Kim, Jae Ho Yun, Jeong Chul Lee, Kyung Hoon Yoon, “Effects of heat treatments on the properties of Cu(In,Ga)Se2 nanoparticles”, Solar Energy Materials and Solar Cells 91 (2007) 1836-1841
[61]Se Jin Ahn, Ki Hyun Kim, Kyung Hoon Yoon, “Cu(In,Ga)Se2 thin film solar cells from nanoparticle precursors”, Current Applied Physics 8 (2008) 766-769.
[62]Reid A. Mickelsen and Wen S. Chen, “Methods for forming thin-film heterojunction solar cells from I- III-VI2 chalcopyrite compound”, and solar cells produced thereby. US, Patent No: 4335266, (1982).
[63]Reid A. Mickelsen and Wen S. Chen, “Thin film CdS/CuInSe2 heterojunction solar cell”, Proceedings of the Society of Photo-Optical Instrumentation Engineers 248 (1980) 62-69.
[64]F.S. Hasoon, Y. Yan, H. Althani, K.M. Jones, H.R. Moutinho, J. Alleman, M.M. Al-Jassim, R. Noufi,“Microstructural properties of Cu (In,Ga)Se2 thin films used in high-efficiency devices”, Thin Solid Films 387 (2001) 1-5.
[65]Neelkanth G. Dhere, “Present status and future prospects of CIGSS thin film solar cells”, Solar Energy Materials and Solar Cells 90 (2006) 2181-2190.
[66]Neelkanth G. Dhere, Ankur. A. Kadam, “Thin film solar cells by selenization sulfurization using diethyl selenium as a selenium precursor”, US, Patent No: US20070257255A1, (2007).
[67]T. Kume, T. Komaru, “Process for producing light absorbing layer for chalcopyrite type thin- film solar cell”, JP, Patent No: US20080035199A1, (2008).
[68]Y. Hamakawa (ed.), “Thin-film solar cells : next generation photovoltaics and its applications”, New York : Springer, (c2004). p183.
[69]Chopra, K. L., P. D. Paulson, and V. Dutta. “Thin-film solar cells: an overview.” Progress in Photovoltaics: Research and Applications 12 (2004) 69-92.
[70]Milton Ohring “Materials science of thin films: deposition and structure”, San Diego, CA : Academic Press, 2001. chapter 10, pp.559-640.
[71]H. P. Klug, L. Alexander, “X-Ray Diffraction Procedures for Polycrystalline and Amorphous Materials”, second ed., John Wiley and Sons, New York, 1974, p. 656.
[72]Z. F. Liu, F. K. Shan, J. Y. Sohn, S. C. Kim, G. Y. Kim, Y. X. Li, Y. S. Yu, “Photoluminescence of ZnO: Ga thin films fabricated by pulsed laser deposition technique,” Journal of Electroceramics”, Journal of Electroceramics 13 (2004) 183-187.
[73]K. Koski, J. Holsa, P. Juliet, “Surface defects and arc generation in reactive magnetron sputtering of aluminium oxide thin films”, Surface and Coatings Technology 115 (1999) 163-171.
[74]H. Zhang, T.L. Yang, J. Ma, Q. P. Wang, R. W. Gao, H.L. Ma,“Preparation of transparent conducting ZnO:Al films on polymer substrates by r. f. magnetron sputtering”, Applied Surface Science 158 (2000) 43-48.
[75]E. Fortunato, V. Assuncao, A. Goncalves, A. Marques, H. Aguas, L. Pereira, I. Ferreira, P. Vilarinho, R. Martins, “High quality conductive gallium-doped zinc oxide films deposited at room temperature”, Thin Solid Films 451-452 (2004) 443-447.
[76]X. Xiu, Z. Pang, M. Lv, Y. Dai, L. Ye, S. Han,“Transparent conducting molybdenum-doped zinc oxide films deposited by RF magnetron sputtering”, Applied Surface Science 253 (2007) 3345-3348.
[77]D. Jiles, “Introduction to the Electronic Properties of Materials”, Chapman and Hall,(1994) chap.9.p180.
[78]E. Burstein, “Anomalous Optical Absorption Limit in InSb”, Physical Review B 93 (1954) 632-633.
[79]A. Segura, J. A. Sans, D. Errandone, D. Martinez-Garcí, and V. Fages, “High conductivity of Ga-doped rock-salt ZnO under pressure: Hint on deep-ultraviolet-transparent conducting oxides”, Applied Physics Letters 88 (2006) 011910-1-011910-3.
[80]A.P. Roth, J.B. Webb, and D.F. Williams, “Band gap narrowing in heavily defect doped ZnO”, Physical Review. B 25 (1982) 7836-7839.
[81]D. R. Sahu, S.Y. Lin, J. L. Huang, “Study on the electrical and optical properties of Ag/Al-doped ZnO coatings deposited by electron beam evaporation ”, Applied Surface Science 253 (2007) 4886-4890.
[82]S. S. Lin, J. L. Huang, P. Sjgalik, “Effects of substrate temperature on the properties of heavily Al-doped ZnO films by simultaneous r.f. and d.c. magnetron sputtering”, Surface and Coatings Technology 190 (2005) 39-47.
[83]J. F. Chang, W. C. Lin, M. H. Hon, “Effects of post-annealing on the structure and properties of Al-doped zinc oxide films”, Applied Surface Science 183 (2001) 18-25.
[84]I. Sieber, N. Wanderka, I. Urban, I. Dorfel, E. Schierhorn, F. Fenske,W. Fuhs, “Electron microscopic characterization of reactively sputtered ZnO films with different Al-doping levels”, Thin Solid Films 330 (1998) 108-113.
[85]G. Masetti, M. Severi, S. Solmi, “Modeling of carrier mobility against carrier concentration in arsenic-, phosphorus- and boron-doped silicon”, IEEE Trans. Electron Devices ED30 (1983) 764-769.
[86]K. Ellmer, A. Klein, B. Rech, “Transparent Conductive Zinc Oxide: Basics and Applications in Thin Film Solar Cells”, Springer, London, (2007), p.62. & p.135.
[87]T. Minami, H. Sato, K. Ohashi, T. Tomofuji, S. Takata,“Conduction mechanism of highly conductive and transparent zinc oxide thin films prepared by magnetron sputtering”, Journal of Crystal Growth 117 (1992) 370-374.
[88]M. N. Islam, T. B. Ghosh, K. L. Chopra, H. N. Acharya,“XPS and X-ray diffraction studies of aluminum-doped zinc oxide transparent conducting films”, Thin Solid Films 280 (1996) 20-25.
[89]K. H. Yoon, J. W. Choi, D. H. Lee, “Characteristics of ZnO thin films deposited onto Al/Si substrates by r.f. magnetron sputtering”, Thin Solid Films 302 (1997) 116-121.
[90]G. E. Hammer, R. M. Shermenski, “The oxidation of zinc in air studied by XPS and AES”, The Journal of Vacuum Science and Technology A 1 (1983) 1026-1028.
[91]P. Erhart, K. Albe, A. Klein, “First-principles study of intrinsic point defects in ZnO: Role of band structure”, Physical Review B73 (2006) 205203-9.
[92]L. Jing, Z. Xu, X. Sun, J. Shang, W. Cai, “The surface properties and photocatalytic activities of ZnO ultrafine particles”, Applied Surface Science 180 (2001) 308-314.
[93]T. Minami, H. Nanto, S. Takata, “Optical Properties of Aluminum Doped Zinc Oxide Thin Films Prepared by RF Magnetron Sputtering”, Japanese Journal of Applied Physics 24 (1985) L605-L607.
[94]Y. Zhang, G. Du, D. Liu, X. Wang, Y. Ma, J. Wang, J. Yin, X. Yang, X. Hou, S. Yang, “Crystal growth of undoped ZnO films on Si substrate under different sputtering conditions”, Journal of Crystal Growth 243 (2002) 439-443.
[95]S. Y. Kuo, W. C. Chen, F. I. Lai, C. P. Cheng, H. C. Kuo, S. C. Wang, W. F. Hsieh, “Effects of Doping Concentration and Annealing Temperature on Properties of Highly-Oriented Al-Doped ZnO Films”, Journal of Crystal Growth 287 (2006) 78-84.
[96]D. Jiles in: Introduction to the Electronic Properties of Materials (Chapmanand & Hall, New York 1994).
[97]M. Giulio, G. Micocei, R. Rella, P. Sikiliano and A. Tepore,“Optical absorption and photoconductovity in amorphous indium selenide thin films”, Thin Solid Films 148 (1987) 273-278.
[98]M. Berginski, J. Hupkes, M. Schulte, G. Schope, H. Stiebig and B. Rech, “The Effect of Front ZnO:Al Surface Texture and Optical Transparency on Efficient Light Trapping in Silicon Thin-Film Solar Cells”, Journal of Applied Physics 101 (2007) 074903-1-11.
[99]C. Agashe, O. Kluth, J. Hüpkes, U. Zastrow, B. Rech, M. Wuttig, “Efforts to improve carrier mobility in radio frequency sputtered aluminum doped zinc oxide films”, Journal of Applied Physics 95 (2004) 1911-1917.
[100]J. Yoo, J. Lee, S. Kim, K. Yoon, I. J. Park, S.K. Dhungel, B. Karunagaran, D. Mangalaraj, J. Yi, “High transmittance and low resistive ZnO:Al films for thin film solar cells”, Thin Solid Films 480-481 (2005) 213-217.
[101]A. Brummer, V. Honkimaki, P. Berwian, V. Probst, J. Palm, R. Hock, “Formation of CuInSe2 by the annealing of stacked elemental layers-analysis by in situ high-energy powder diffraction”, Thin Solid Films 437 (2003) 297-307.
[102]T. Tanaka, T. Yamaguchi, A. Wakahara, A. Yoshida, “Effect of substrate temperature on properties of thin films prepared by RF sputtering from CuInSe2 target with Na2Se”, Thin Solid Films 343-344 (1999) 320-323.
[103]J.A. Thornton, “Influence of apparatus geometry and deposition conditions on the structure and topography of thick sputtered coatings”, The Journal of Vacuum Science and Technology A 11 (1974) 666-670.
[104]T. Yamaguchi, T. Hirao, S. Niiyama, and Y. Miyake, “Cu(In,Ga)(S,Se)2 thin films prepared by thermal crystallization from CuInGaSe/CuGaSe precursor in S/Se atmosphere”, Physica Status Solidi (c) 3 (2006) 2555-2558.
[105]S. Chichibu, T. Shioda, T. Irie, and H. Nakanishi,“Improved optical properties of CuInSe2 thin films prepared by alternate-feeding physical vapor deposition”, Journal of Applied Physics 84 (1998) 522-525.
[106]C. Dzionk, H. Metzner, S. hessler, and H. E. Mahnke,“Phase formation during the reactive annealing of Cu-In films in H2S atmosphere”, Thin Solid Films 299 (1997) 38-44.
[107]O. Lundberg, M. Edoff, L. Stolt, “The effect of Ga-grading in CIGS thin film solar cells”, Thin Solid Films 480-481 (2005) 520-525.
[108]R. Caballero, C. Maffiotte, C. Guillen, “Preparation and characterization of CuIn1-xGaxSe2 thin films obtained by sequential evaporations and different selenization processes”, Thin Solid Films 474 (2005) 70-76.
[109]F.O. Adurodija, M.J. Cater, R. Hill, “Synthesis and characterization of CuInSe2 thin films from Cu, In and Se stacked layers using a closed graphite box”, Solar Energy Materials and Solar Cells 40 (1996) 359-369.
[110]S.D. Kim, H.J. Kim, K.H. Yoon, J. Song, “Effect of selenization pressure on CuInSe2 thin films selenized using co-sputtered Cu-In precursors”, Solar Energy Materials and Solar Cells 62 (2000) 357-368.
[111]I. Dirnstorfer, W. Burkhardt, W. Kriegseis, I. OE sterreicher, H. Alves, D.M. Hofmann, O. Ka, A. Polity, B.K. Meyer, D. Braunger, “Annealing studies on CuIn(Ga)Se2: the influence of gallium”, Thin Solid Films 361-362 (2000) 400-405.
[112]R. Wieting, R. Gay, H. Nguyen, J. Palm, C. Rischmiller, A. Seapan, D. Tarrant, D. Willett, Proceedings of the 31st Photovoltaic Specialists Conference, Hawaii, (2005) p.177.
[113]Bernhand Dimmler, Michael Powalla, Raymond Schaetter, Proceedings of the 31st Photovoltaic Specialists Conference, Hawaii, (2005) p.189.
[114]E. Ahmed, A. Zegadi, A.E. Hill, R.D. Pilkington, R.D. Tomlinson, A.A. Dost, W. Ahmed, S. Lepphvuori, J. Levoska, O. Kusmartseva, “Impact of annealing processes on the properties of CuIn0.75Ga0.25Se2 thin films”, Solar Energy Materials and Solar Cells 36 (1995) 227-239.
[115]L. Zhang, Q. He, W.L. Jiang, F.F. Liu, C.J. Li, Y. Sun, “Effects of substrate temperature on the structural and electrical properties of Cu(In,Ga)Se2 thin films”, Solar Energy Materials and Solar Cells 93 (2009) 114-118.
[116]S. Sirohi, T.P. Sharma, “Band gaps of cadmium telluride sintered film”, Optical materials 13 (1999) 267-269.
[117]A. Zegadi, M.A. Slifkin, M. Djamin, R.D. Tomlinson, and H. Neumann, “Photoacoustic spectroscopy of defect states in CuInSe2 single crystals”, Solid State Communication 83 (1992) 587-591.
[118]J. Muller, J. Nowoczin, H. Schmitt, “Composition, structure and optical properties of sputtered thin films of CuInSe2”, Thin Solid Films 496 (2006) 364-370.
[119]S.J. Ahn, C.W. Kim, J.H. Yun, J.C. Lee, K.H. Yoon,“Effects of heat treatments on the properties of Cu(In,Ga)Se2 nanoparticles”, Solar Energy Materials and Solar Cells 91 (2007) 1836-1841.
[120]G. Hanna, A. Jasenek, U. Rau, H.W. Schock, “Influence of the Ga-content on the bulk defect densities of Cu(In,Ga)Se2”, Thin Solid Films 387 (2001) 71-73.
[121]Y. M. Strzhemechny, P. E. Smith, S. T. Bradley, D. X. Liao, A. A. Rockett, K. Ramanathan and L. J.
Brillson, “Near-surface electronic defects and morphology of CuIn1-xGaxSe2”, The Journal of Vacuum Science and Technology B 20 (2002) 2441-2448.