銅鋅錫硫硒是由含量豐富的鋅、錫取代銅銦鎵硫硒中的貴重金屬銦、鎵，已成為下世代有潛力的太陽能材料之一。目前以IBM的聯氨溶液法製備的銅鋅錫硫硒12.6%為最高效率。雖然非真空溶液法可以降低設備成本及高的材料利用率和產能，但聯氨具有高毒性及爆炸性，所以尋找便宜、穩定及非毒性的溶液製程有必要性。
本研究建立非真空銅鋅錫硫無毒溶劑前驅物製程。這裡發展兩種不同製程並得到相關機制與性質如下：
(A)銅鋅錫硫奈米粉體
(1)成功製備銅鋅錫硫奈米粉體並研究熱處理相變化。藉由提高前驅物的錫含量，可以有效解決熱處理時錫損失問題，並得到單一銅鋅錫硫相。
(2)利用硫化製程提高銅的向後擴散，再進行硒化處理得到大顆且緊密排列的銅鋅錫硫結晶，改善直接硒化的分層問題。

(B)乙二醇單甲醚溶液法
(1)成功製備乙二醇單甲醚前驅物溶液並探討前驅物溶液的穩定性。
(2)在硫化熱處理時維持富硫環境可大幅降低硫化時間，得到大顆且緊密排列的結晶。
(3)在銅鋅錫硫前驅物與鉬基板間置入一層退火後的硫化錫，可有效避免銅鋅錫硫吸收層與鉬基板間的孔洞形成，進一步改善元件的開路電壓與填充因子。
(4)開發硒化前硫化技術，形成大且緊密的晶粒解決銅鋅錫硫硒的分層問題，修飾晶界提高載子傳輸，並減少硫硒化鉬的厚度，效率可達10.1%
(5)將經硒化前硫化製程後的銅鋅錫硫硒薄膜進行硫化後處理，可使吸收層表面形成高硫含量的銅鋅錫硫硒，提高吸收層能隙並減少開路電壓損失。當硫含量提高至40%時，元件效率可提升至11.1%，為本論文最大突破且是目前國內銅鋅錫硫硒太陽能電池最高效率。

Thin-film kesterite Cu2ZnSn(S,Se)4 (CZTSSe) solar cells, in which the indium and gallium in Cu(In,Ga)(S,Se)2 (CIGSSe) is replaced with abundant and cheap zinc and tin, has become as a potential absorber material in next generation. Recently, CZTSSe solar cells with efficiencies of 12.6 % were reported by IBM employing a hydrazine-based solution process. However, the hydrazine is highly toxic and explosive. Although non-vacuum solution processes already exhibit low equipment cost, high material utilization and high throughput, an inexpensive, reliable, and non-toxic solution process is desirable.

　　　　Consequently, this work is to establish a non-vacuum process without toxic precursor solvents. Two different processes are studied and relevant mechanisms and properties are also presented:
(A) Cu2ZnSnS4 nano-particles
(1) Non-crystalline CZTS nano-particles were fabricated and phase transformation behaviors were treated by different sulfurization conditions. Sn loss during heat treatment was solved by increasing Sn content of the precursors, and pure CZTS phase was obtained.
(2) Pre-sulfurization enhanced Cu backward diffusion. Then high temperature selenization enhanced the formation of compact and large CZTS grains, the problem of fine grains layer in the bottom was improved.

(B) 2-Methoxyethanol-based solution process.
(1) EGME-based solutions were synthesized and the stability of solutions was studied.
(2) Sulfurization time was reduced using the sulfur-rich heat treatment condition, and a large CZTS grains were obtained without second phase.
(3) The annealed SnS layer improved the CZTS quality by eliminating the voids at the CZTS–MoS2 interface. The open-circuit voltage and fill factor were further increased.
(4) Sulfurization before selenization effectively forms a compact CZTSSe layer that eliminated the fine-grain bottom layer, modifies of the grain boundary chemistry that might change carrier extraction, and decreased the thickness of the MoSSe2 interlayer, improving the cell efficiency. The efficiency of CZTSSe solar cell was 10.1%.
(5) A CZTSSe layer with a higher sulfur content than the bulk was found near the surface was formed by post-sulfurization. The bi-layer structure increased the bandgap of absorber and decreased the Voc-deficit. When the sulfur content was 40% (x = 0.4), the CZTSSe solar cell had an efficiency of 11.1% which is the important breakthrough in this reaserch and the highest efficiency record in Taiwan.

[1] United Nations (2015), Guidebook on promotion of sustainable energy consumption: consumer organizations and efficient energy use in the residential sector, United Nations, New York.
[2]Asim N, Sopian K, Ahmadi S, Saeedfar K, Alghoul MA, and Saadatian O (2012), “A review on the role of materials science in solar cells,” Renew Sustain Energy Rev (16)pp. 5834~5847.
[3] Dhakal TP, Peng CY, Reid Tobias R, Dasharathy R, and Westgate CR. (2014) “Characterization of a CZTS thin film solar cell grown by sputtering method,” Sol Energy (100) pp.23~30.
[4]Thimsen EJ. Energy E, and Engineering C. (2009) “Metal oxide semiconductors for solar energy harvesting,” Washington University in St. Louis.
[5] International Energy Agency Publications (2011) “Solar Energy Perspectives, Technical report.”
[6] https://www.iea.org/publications/freepublications/publication/pv_roadmap.pdf.
[7] Rahman MZ. (2014) “Advances in surface passivation and emitter optimization techniques of c-Si solar cells,” Renew Sustain Energy Rev (30) pp.734~742
[8] M. A. Green, K. Emery, Y. Hishikawa, W. Warta and E. D. Dunlop (2013), “Solar cell efficiency tables (version 42),” Progress in Photovoltaics: Research and Applications (21) pp.827
[9] P. Jackson, D. Hariskos, R. Wuerz, O. Kiowski, A. Bauer, T. M. Friedlmeier, and M. Powalla (2015), “Properties of Cu(In,Ga)Se2 solar cells with new record efficiencies up to 21.7%, Phys. Status Solidi RRL (9) pp.28-31.
[10] Green, M. A., Emery, K., Hishikawa, Y., Warta, W. and Dunlop, E. D. (2014) “Solar cell efficiency tables (version 44): Solar cell efficiency tables,” Progress in Photovoltaics: Research and Applications (22) pp.701–710.
[11] www.firstsolar.com
[12] M.J.Shiao (2014), “First Solar Hits Record 22.1% Conversion Efficiency for CdTe Solar Cell.”
[13] http://www.solar-frontier.com
[14] http://www.thesolarclothcompany.com
[15] http://www.globalsolar.com/
[16] A. Colthorpe (2014), “Solar Frontier’s record efficiency 22.3% CIG cell faces global market challenge”
[17] M. Osborne (2015), “ZSW achieves world record CIGS lab cell efficiency of 22.6%.
[18] NREL (2017),”Best-Research-Cell Efficiencies.”
[19] V. M. Fthenakis and P. D. Moskowitz (1995), “Thin-film Photovoltaic Cells: Health and Environmental Issues in their Manufacture Use and Disposal,” Progress in Photovoltaics: Research and Applications, (3) pp. 295-306.
[20] S. Chen, X. G. Gong, A. Walsh and S.-H. Wei (2009), “Electronic structure and stability of quaternary chalcogenide semiconductors derived from cation cross-substitution of II-VI and I-III-VI2 compounds,” Phys. Rev. B, (79) pp.165211.
[21] Wang H. (2011) “Progress in thin film solar cells based on Cu2ZnSnS4.” Into Photo energy.
[22] Kodigala SR. (2013) “Thin film solar cells from earth abundant materials : growth and Characterization of Cu2(ZnSn)(SSe)4 thin films and their solar cells.” Elsevier Science
[23] S. Schorr (2011),“The crystal structure of kesterite type compounds: a neutron and X-ray diffraction study, Solar Energy Materials and Solar Cells, 95(6) pp. 1482–1488
[24] C. Persson (2010), Electronic and optical properties of Cu2ZnSnS4 and Cu2ZnSnSe4, Journal of Applied Physics (107) pp.053710.
[25] S. Chen, A. Walsh, J.-H. Yang, X. G. Gong, L. Sun, P.-X. Yang, J.-H. Chu and
S.-H. Wei (2011), “Compositional dependence of structural and electronic properties of Cu2ZnSn(S,Se)4 alloys for thin film solar cells,” Phys. Rev. B (83) pp.125201.
[26] D. B. Mitzi, O. Gunawan, T. K. Todorov, K.Wang and S. Guha (2011), “The path towards a high-performance solution-processed kesterite solar cell,” Solar Energy Materials and Solar Cells (95) pp.1421.
[27] I. D. Oleksyuk, I. V. Dudchar and L. V. Piskach, (2004) “Phase equilibria in the Cu2S–ZnS–SnS2 system,” Journal of Alloys and Compounds (368) pp. 135-143.
[28] I. V. Dudchak and L. V. Piskach (2003), “Phase equilibria in the Cu2SnSe3–SnSe2–ZnSe system,” Journal of Alloys and Compounds (351) pp. 145-150.
[29] Scragg, J. J. (2010) “Studies of Cu2ZnSnS4 films prepared by sulphurisation of electrodeposited precursors,” University of Bath, Dissertation.
[30] Wagner, R. Wiemhofer, H. D. (1983) “Hall effect and conductivity in thin films of low temperature chalcocite Cu2S at 20°C as a function of stoichiometry.” Journal of Physics and Chemistry of Solids (44) pp.801–805
[31] Nozaki, H. Shibata, K. Ohhashi, N. (1991) “Metallic hole conduction in CuS.” Journal of Solid State Chemistry (91) pp.306–311
[32] Shibata, T. Muranushi, Y. Miura, T. Kishi, T. (1990) “Photoconductive properties of single-crystal 2H-SnS2.” Journal of Physics and Chemistry of Solids (51) pp.1297–1300.
[33] W. Ahmed M.Y. Nadeem (2000), “Optical properties of ZnS thin films,” Journal of Physics (24) pp.651-659.
[34] Washio, T. (2012), “6% Efficiency Cu2ZnSnS4-based thin film solar cells using oxide precursors by open atmosphere type CVD.” Journal of Materials Chemistry (22) pp.4021.
[35] A. Lafond, L. Choubrac, C Guillot-Deudon, P. Fertey, M. Evain, and S. Jobic, (2014) “X-ray resonant single crystal diffraction technique, a powerful tool to investigate the kesterite structure of the photovoltaic Cu2ZnSnS4 compound,” Acta Crystallogr B Struct Sci Cryst Eng Mater. (70) pp.390-394.
[36] T.Gokmen, O. Gunawan, T. K. Todorov, and D. B. Mitzi, (2013) “Band tailing and efficiency limitation in kesterite solar cells,” Appl. Phys. Lett. (103) pp.103506
[37] F. Kessler, and D. Herrmann, (2005) “Approaches to flexible CIGS thin-film solar cells” Thin Solid Films (480-481) pp.491-498
[38] M.A. Green, K. Emery, Y. Hishikawa, and W. Warta, (2010) “Solar cells efficiency tables (version 36),” Prog. Photovoltaics: Res. Appl. (18) pp.346–352.
[39] M.A. Green, (2009) “Estimates of Te and In prices from direct mining of known ores” Prog. Photovoltaics: Res.Appl. (17) pp.347-359.
[40] S. C. Riha, B. A. Parkinson, and A. L. Prieto,(2011) “Compositionally Tunable Cu2ZnSn(S1−xSex)4Nanocrystals: Probing the Effect of Se-Inclusion in Mixed Chalcogenide Thin Films.” J. Am. Chem. Soc. (133) pp.15272-15275.
[41] Q. J. Guo, H.W. Hillhouse, and R. Agrawal,(2009) “Synthesis of Cu2ZnSnS4 Nanocrystal Ink and Its Use for Solar Cells” J. Am. Chem. Soc. (131) pp.11672-11673
[42] K. Wang, O. Gunawan, T. Todorov, B. Shin, S.J. Chey, N.A. Bojarczuk, D. Mitzi, and S. Guha,(2010) “Thermally evaporated Cu2ZnSnS4 solar cells” Appl.Phys.Lett. (97) pp.143508.
[43] H. Katagiri, K. Jimbo, S. Yamada, T. Kamimura, W.S. Maw, T. Fukano, T. Ito, T. Motohiro,(2008) “Development of CZTS-based thin film solar cells” Appl.Phys.Express1 pp.41201.
[44] A.V. Moholkar, S.S. Shinde, A.R. Babar, Kyu-Ung Sim, Hyun Kee Lee, K.Y. Rajpure, P.S. Patil, C.H. Bhosale, and J.H. Kim,(2011) “Synthesis and characterization of Cu2ZnSnS4 thin films grown by PLD: Solar cells” J. Alloys Compd. (509) pp.7439-7446
[45] Q. Guo, G. M. Ford, W. C. Yang, B. C. Walker, E. A. Stach, H. W. Hillhouse, and R. Agrawal,(2010) “Fabrication of 7.2% efficient CZTSSe solar cells using CZTS nano-crystals,” J. AM. CHEM. SOC. (132) pp.17384-17386
[46] M. Jeon, T. Shimizu, and S. Shingubara,(2011) “Formation and characterization of single-step electrodeposited Cu2ZnSnS4 thin films: Effect of complexing agent volume” Mater. Lett. (65) pp.2364-2367
[47] S. C. Riha, B. A. Parkinson, and A. L. Prieto, (2009) “Solution-Based Synthesis and Characterization of Cu2ZnSnS4 Nanocrystals,” J. AM. CHEM. SOC. (131) 12054–12055
[48] T. Kameyama, T. Osaki, K.I. Okazaki, T. Shibayama, A. Kudo, S. Kuwabata and T. Torimoto,(2010) “A heating-up method for the synthesis of pure phase kesterite Cu2ZnSnS4 nanocrystals using a simple coordinating sulphur precursor,” J. Mater. Chem. (20) pp.5319–5324
[49] A. Shavel,D. Cadavid, M. Ibanez, A. Carrete, and A. Cabot,(2012) “Continuous Production of Cu2ZnSnS4 Nanocrystals in a Flow Reactor,” J. Am. Chem. Soc. (134) pp.1438−1441.
[50] Y. L. Zhou, W. H. Zhou, M. Li, Y. F. Du, and S. X. Wu, (2011) “Hierarchical Cu2ZnSnS4 Particles for a Low-Cost Solar Cell: Morphology Control and Growth Mechanism,” J. Phys. Chem. C (115) pp.19632–19639
[51] T. K. Todorov, K. B. Reuter, and D. B. Mitzi,(2010) “High-efficiency solar cell with Earth-abundant liquid-processed absorber.” Adv. Mater. (22) pp.1-4
[52] R. Schurr, A. Hölzing, S. Jost, R. Hock, T. Voß, J. Schulze, A. Kirbs, A. Ennaoui, M. Lux-Steiner, A. Weber, I. Kötschau, and H.-W. Schock,(2009) “The crystallisation of Cu2ZnSnS4 thin film solar cell absorbers from co-electroplated Cu–Zn–Sn precursors,” Thin Solid Films (517) pp.2465.
[53] R. Schurr , A. Hölzing, and R. Hock,(2011) “Real-time investigations on the formation reactions during annealing of sulfurized Cu–Sn precursors,” Thin Solid Films (519) pp.7412-7415
[54] A. Weber, R. Mainz, and H. W. Schock,(2010) “On the Sn loss from thin films of the material system Cu–Zn–Sn–S in high vacuum,” J. Appl. Phys. (107) pp.013516.
[55] M. Altosaar, J. Raudoja, K. Timmo, M. Danilson, M. Grossberg, J. Krustok, and E. Mellikov,(2008) “Cu2Zn1–xCdxSn(Se1–ySy)4 solid solutions as absorber materials for solar cells,” Phys. Stat. Sol. (a) (205) pp.167.
[56] P.A. Fernandes, P.M.P. Salome, amd A.F. da Cunha,(2011) “Study of polycrystalline Cu2ZnSnS4 films by Raman scattering,” J. Alloys Compd. (509) pp. 7600-7606
[57] W. Wang, M. T. Winkler, O. Gunawan, T. Gokmen, T. K. Todorov, Y. Zhu, and D. B. Mitzi,(2014) “Device characteristics of CZTSSe thin‐film solar cells with 12.6% efficiency,” Advanced Energy Materials (4) pp.1301465.
[58] S. W. Shin, J. H. Han, C. Y. Park, A. V. Moholkar, J. Y. Leea, and J. H. Kimb,(2012) “Quaternary Cu2ZnSnS4 nanocrystals: facile and low cost synthesis by microwave-assisted solution method,” J. Alloys Compd. (516) pp.96-101
[59] S. H. Wu, C. W. Chang, H. J. Chen, C. F. Shih, Y. Y. Wang, C. C. Li, and S. W. Chan,(2016) “High-efficiency Cu2ZnSn(S,Se)4 solar cells fabricated through a low-cost solution process and a two-step heat treatment,” Prog. Photovoltaic Res. Appl. (10) pp.1002.
[60] D. Park, D. Nam, S. Jung, S. An, J. Gwak, K. Yoon, J. H. Yun, and H. Cheong (2011) “Optical characterization of Cu2ZnSnSe4 grown by thermal co-evaporation,” Thin Solid Films (519) pp.7386–7389.
[61] P. Tonndorf, R. Schmidt, P. Böttger, X. Zhang, J. Börner, A. Liebig, M. Albrecht, C. Kloc, O. Gordan, D. R. T. Zahn, S. M. de Vasconcellos, and R. Bratschitsch (2013) “Photoluminescence emission and Raman response of monolayer MoS2, MoSe2, and WSe2” Optics Express (21) pp.4908
[62] H. Cui, X. Liu, F. Liu, X. Hao, N. Song, and C. Yan (2014) “Boosting Cu2ZnSnS4 solar cells efficiency by a thin Ag intermediate layer between absorber and back contact,” Applied Physics Letters (104) pp.041115
[63] J. Zhong, Z. Xia, M. Luo, J. Zhao, J. Chen, L. Wang, X. Liu, D. J. Xue, Y. B. Cheng, H. Song, and J. Tang (2014) “Sulfurization induced surface constitution and its correlation to the performance of solution-processed Cu2ZnSn(S, Se)4 solar cells” Sci. Rep. (4) pp.6288.
[64] Y. S. Lee, T. Gershon, O. Gunawan, T. K. Todorov, T. Gokmen, Y. Virgus, and S. Guha (2015) “Cu2ZnSnSe4 thin-film solar cells by thermal coevaporation with 11.6% effi ciency and improved minority carrier diffusion length,” Advanced Energy Materials (5) pp.1401372.
[65] H. Sugimoto, C. Liao, H. Hiroi, N. Sakai, and T. Kato (2013) “Lifetime improvement for high efficiency Cu2ZnSnS4 submodules,” Proc. PVSC (39).
[66] S. Tajima, M. Umehara, M. Hasegawa, T. Mise, and T. Itoh (2017) “Cu2ZnSnS4 photovoltaic cell with improved efficiency fabricated by high-temperature annealing after CdS buffer-layer deposition,” Prog. Photovolt. Res. Appl. (25) pp.14-22.
[67] S.G. Haass, M. Diethelm, M. Werner, B. Bissig, Y.E. Romanyuk, and A.N. Tiwari (2015) “11.2% Efficient solution processed kesterite solar cell with a low voltage deficit,” Adv. Energy Mater. pp.1500712.
[68] H. Xin, J.K. Katahara, I.L. Braly, H.W. Hillhouse (2014) “8% Efficient Cu2ZnSn(S,Se)4 solar cells from redox equilibrated simple precursors in DMSO,” Adv. Energy Mater. pp.1301823.
[69] S. Siebentritt (2013) “Why are kesterite solar cells not 20% efficient?” Thin Solid Films (535) pp.1-4.
[70] S. Tajima, M. Umehara, T. Mise, Jpn (2016) “Photovoltaic properties of Cu2ZnSnS4 cells fabricated using ZnSnO and ZnSnO/CdS buffer layers,” J. Appl. Phys. (55) pp.112302.
[71] Z. Su, K. Sun, Z. Han, H. Cui, F. Liu, Y. Lai, J. Li, X. Hao, Y. Liu, M.A. Green (2014) “Fabrication of Cu2ZnSnS4 solar cells with 5.1% efficiency via thermal decomposition and reaction using a non-toxic solegel route,” J. Mater. Chem. A (2) pp.500-509
[72] G. Larramona, S. Levcenko, S. Bourdais, A. Jacob, C. Chon_e, B. Delatouche,
C. Moisan, J. Just, T. Unold, and G. Dennler (2015) “Fine-tuning the Sn content in CZTSSe thin films to achieve 10.8% solar cell effi ciency from spray-deposited water ethanol-based colloidal inks,” Adv. Energy Mater. (5) pp.1501404.
[73] J.J. Scragg, J.T. Watjen, M. Edoff, T. Ericson, T. Kubart, and C. Platzer-Bjorkman (2012) “A detrimental reaction at the molybdenum back contact in Cu2ZnSn (S, Se)4 thin-film solar cells,” J. Am Chem. Soc. (134) pp.19330–19333.
[74] S.L. Marino, M. Placidi, A.P. Tomas, J. Llobet, V.I. Roca, X. Fontane, A. Fairbrother, M.E. Rodríguez, D. Sylla, A.P. Rodríguez, and E. Saucedo (2013) “Inhibiting the absorber/Mo-back contact decomposition reaction in Cu2ZnSnSe4 solar cells: the role of a ZnO intermediate nanolayer,” J. Mater. Chem. A (1) pp.8338–8343
[75] J.J. Scragg, T. Kubart, J.T. Wätjen, T. Ericson, M.K. Linnarsson, C. Platzer- Björkman (2013) “Effects of back contact instability on Cu2ZnSnS4 devices and processes,” Chem. Mater. (25) pp.3162–3171.
[76] F. Liu, K. Sun, W. Li, C. Yan, H. Cui, L. Jiang, H. Hao, and M.A. Green (2014) “Enhancing the Cu2ZnSnS4 solar cell efficiency by back contact modification: Inserting a thin TiB2 intermediate layer at Cu2ZnSnS4/Mo interface,” Appl. Phys. Lett. (104) pp.051105.
[77] H.J. Chen, S.W. Fu, S.H. Wu, T.C. Tsai, H.T. Wu, and C.F. Shih (2016) “Impact of SnS Buffer Layer at Mo/Cu2ZnSnS4 Interface,” J. Am. Ceram. Soc. (99) pp.1808–1814.
[78] Vauche L, Risch L, Sánchez Y, Dimitrievska M, Pasquinelli M, de Monsabert TG, Grand PP, Ferrer SJ, and Saucedo E. (2016) “8.2% pure selenide kesterite thin-film solar cells from large-area electrodeposited precursors.” Progress in Photovoltaics: Research and Applications (24) pp.38–51.
[79] Jiang F, Ikeda S, Harada T, and Matsumura M (2014) “Pure sulfide Cu2ZnSnS4 thin film solar cells fabricated by preheating an electrodeposited metallic stack,” Advanced Energy Materials (4) pp.1301381–1301384.
[80] Guo Q, Hillhouse HW, and Agrawal R (2009) “Synthesis of Cu2ZnSnS4 nanocrystal ink and its use for solar cells,” Journal of the American Chemical Society (131) pp.11672–11673.
[81] G. Larramona, S. Levcenko, S. Bourdais, A. Jacob, C. Chon_e, B. Delatouche,
C. Moisan, J. Just, T. Unold, and G. Dennler (2015) “Fine-tuning the Sn content in CZTSSe thin films to achieve 10.8% solar cell effi ciency from spray-deposited water ethanol-based colloidal inks,” Adv. Energy Mater. (5) pp.1501404.
[82] Hsu CJ, Duan HS, Yang W, Zhou H, Yang Y. (2014) “Benign solutions and innovative sequential annealing processes for high performance Cu2ZnSn(Se,S)4 photovoltaics.” Advanced Energy Materials (4) pp.1301287–1301293.
[83] Su Z, Sun K, Han Z, Cui H, Liu F, Lai Y, Li J, Hao X, Liu Y, and Green MA (2014) “Fabrication of Cu2ZnSnS4 solar cells with 5.1% efficiency via thermal decomposition and reaction using a non-toxic sol–gel route.” Journal of Materials Chemistry A (2) 500–509.
[84] Ou KL, Fan JC, Chen JK, Huang CC, Chen LY, Ho JH, and Chang JY (2012) “Hot-injection synthesis of monodispersed Cu2ZnSn(SxSe1-x)4 nanocrystals: tunable composition and optical properties.” Journal of Materials Chemistry (22) pp.14667–14673.
[85] Vani VPG, Reddy MV, and Reddy KTR (2013) “Thickness dependent physical properties of co-evaporated Cu4SnS4 films.” ISRN Condensed Matter Physics pp.142029..
[86] Hsu WC, Repins I, Beall C, DeHart C, To B, Yang W, Yang Y, Noufi R. (2014) “Growth mechanisms of co-evaporated kesterite: a comparison of Cu-rich and Zn-rich composition paths.” Progress in Photovoltaics: Research and Applications (22) 35–43.
[87] Kim GY, Kim JR, Jo W, Son D-H, Kim D-H, and Kang J-K. (2014) “Nanoscale observation of surface potential and carrier transport in Cu2ZnSn(S,Se)4 thin films grown by sputtering-based two-step process.” Nanoscale Research Letters (9) pp.10–14.
[88] Xin H, Vorpahl SM, Collord AD, Braly IL, Uhl AR, Krueger BW, Ginger DS, and Hillhouse HW. (2015) “Lithium doping inverts the nanoscale electric field at the grain boundaries in Cu2ZnSn(S,Se)4 and increases photovoltaic efficiency.” Physical Chemistry Chemical Physics (17) pp.23859–23866.
[89] Isah KU, Yabagi JA, Ahmadu U, Kimpa MI, Kana MGZ, and Oberafo AA.(2013) “Effect of different copper precursor layer thickness on properties of Cu2ZnSnS4 (CZTS) thin films prepared by sulfurization of thermally deposited stacked metallic layers.” IOSR Journal of Applied Physics (2) pp.14–19.
[90] Sagade AA, and Sharma R. (2008) “Copper sulphide (CuxS) as an ammonia gas sensor working at room temperature.” Sensors and Actuators B (133) pp.135–143.
[91] F. J. Fan, L. Wu, M. Gong, G. Liu, Y. X. Wang, S. H. Yu, S. Chen, L. W. Wang, and X. G. Gong (2013) „Composition-and Band-Gap-Tunable Synthesis of Wurtzite-Derived Cu2ZnSn (S1–x Se x)4 Nanocrystals: Theoretical and Experimental Insights,” ACS Nano (2) pp.1454-1463
[92] H. S. Duan, W. Yang, B. Bob, C. J. Hsu, B. Lei, and Y. Yang (2013) “The Role of Sulfur in Solution-Processed Cu2ZnSn(S,Se)4 and its Effect on Defect Properties,” Adv. Funct. Mater. (23) pp.1466-1471.
[93] O. P. Singh, N. Vijayan, K. N. Sood, B. P. Singh, and V. N. Singh (2015) “Controlled substitution of S by Se in reactively sputtered CZTSSe thin films for solar cells,” J. Alloys Compd. (648) pp.595-600
[94] G. Chen, J. Li, M. Wu, J. Liu, F. Lai, and C. Zhu (2015) “Effect of post sulfurization temperature on the microstructure of Cu2ZnSn(S,Se)4 thin film,” Materials Letters (159) pp.32-34.
[95] S. M. Lee, and Y. S. Cho (2013) „Characteristics of Cu2ZnSnSe4 and Cu2ZnSn (Se, S)4 absorber thin films prepared by post selenization and sequential sulfurization of co-evaporated Cu–Zn–Sn precursors,” J. Alloys Compd. (579) pp.279-283.
[96] O. Gunawan, T. Gokmen, C. W. Warren, J. D. Cohen, T. K. Todorov, D. A. R. Barkhouse, S. Bag, J. Tang, B. Shin, and D. B. Mitzi (2012) “Electronic properties of the Cu2ZnSn(Se,S)4 absorber layer in solar cells as revealed by admittance spectroscopy and related methods,” Appl. Phys. Lett. (100) pp.253905
[97] R. Haight, A. Barkhouse, O. Gunawan, B. Shin, and M. Copel (2011) “Band alignment at the Cu2ZnSn(SxSe1-x)4/CdS interface,” Appl. Phys. Lett. (98) pp.253502
[98] Y. Yang, G. Wang, W. Zhao, Q. Tian, L. Huang, and D. Pan (2015) “Solution-Processed Highly Efficient Cu2ZnSnSe4 Thin Film Solar Cells by Dissolution of Elemental Cu, Zn, Sn, and Se Powders,” ACS Appl. Mater. Interfaces (7) pp.460-464.
[99] S. Oueslati, G. Brammertz, M. Buffière, H. ElAnzeery, O. Touayar, C. Köble, J. Bekaert, M. Meuris, and J. Poortmans (2015) “Physical and electrical characterization of high-performance Cu2ZnSnSe4 based thin film solar cells,” Thin Solid Films (582) pp.224-228
[100] B. Ananthoju, J. Mohapatra, M. K. Jangid, D. Bahadur, N. V. Medhekar, M. Aslam (2016) “Cation/Anion Substitution in Cu2ZnSnS4 for Improved Photovoltaic Performance,” Sci. Rep. (6) pp.35369.
[101] P. M. P. Salome, J. Malaquias, P. A. Fernandes, M. S. Ferreira, A. F. da Cunha, J. P. Leitao, J. C. Gonzalez, and F. M. Matinaga (2012) “Growth and characterization of Cu2ZnSn(S, Se)4 thin films for solar cells,” Sol. Energy Mater. Sol. Cells (101) pp.147-153.
[102] S. Ji, T. Shi, X. Qiu, J. Zhang, G. Xu, C. Chen, Z. Jiang, and C. Ye (2013) “A Route to Phase Controllable Cu2ZnSn(S1−xSex)4 Nanocrystals with Tunable Energy Bands,” Sci. Rep. (3) pp.2733.
[103] T. Kobayashi, H. Sugimoto, T. Kato, H. Hakuma, T. Nakada (2014) “Effects of combined heat and light soaking on device performance of Cu(In, Ga)Se2 solar cells with ZnS (O, OH) buffer layer,” 23rd International Photovaltaic Science and Engineering Conference
[104] T. Nakada, H. Ohbo, T. Watanabe, H. Nakazawa, M. Matsui, and A. Kunioka (1997) “Improved Cu(In,Ga)(S,Se)2 thin film solar cells by surface sulfurization,” Sol. Energy Mater. Sol. Cells (49) pp.285-290.
[105] R. A. Sinton, and A. Cuevas (1996) “Contactless determination of current–voltage characteristics and minority‐carrier lifetimes in semiconductors from quasi‐steady‐state photoconductance data,” Appl. Phys. Lett. (69) pp.2510-2512.
[106] T. Walter, R. Herberholz, C. Muller, and H. W. Schock (1996) “Determination of defect distributions from admittance measurements and application to Cu(In,Ga)Se2 based heterojunctions,” J. Appl. Phys. (80) pp.4411.
[107] S. Das, S. K. Chaudhuri, R. N. Bhattacharya, and K. C. Mandal (2014) “Defect levels in Cu2ZnSn(SxSe1−x)4 solar cells probed by current-mode deep level transient spectroscopy,” Appl. Phys. Lett. (104) pp.192106
[108] A. Nagaoka, H. Miyake, T. Taniyama, K. Kakimoto, and K. Yoshino (2013) “Correlation between intrinsic defects and electrical properties in the high-quality Cu2ZnSnS4 single crystal,” Appl. Phys. Lett. (103) pp.112107
[109] S. Levcenko, V. E. Tezlevan, E. Arushanov, S. Schorr, and T. Unold (2012) “Free-to-bound recombination in near stoichiometric Cu2ZnSnS4 single crystals,” Physical Review B (86) pp.045206
[110] V. Nadenau, U. Rau, A. Jasenek, and H. W. Schock (2000) “Electronic properties of CuGaSe2-based heterojunction solar cells. Part I. Transport analysis,” J. Appl. Phys. (87) pp.584.