Study of Structural and Optical Properties of Cu2ZnSnS4 Thin films Synthesized by Spin Sol-Gel

Authors

Abstract

In this study Cu2ZnSnS4 (CZTS) thin films were deposited by sol–gel spin coating on glass substrates and the effect of metal salts ratio, annealing treatment with and without sulfur vapor on  structural, morphological and optical properties of CZTS films were investigated. Our results were showed that all CZTS thin films have kesterite structure.  Moreover increasing of zinc concentration and decreasing of copper content in deposition solution and annealing treatment improved crystallite quality and destructed secondary phases. The band gap energy of the annealed samples was in the range of 1.40 to 1.50 eV, which is convenient for application in solar-cells as an absorber layer. Comparison of the results showed that the morphology, structural and optical properties of annealed CZTS thin films in presence of sulfur are better than other samples.

Keywords


[1] Zentrum fur Sonnenenergie und Wasserstoff- Forschung Baden-Wurttemberg, “ZSW produces a thin-film solar cell with 20.3 percent efficiency”, Press release 08/2010, (2010), Stuttgart, Germany.

[2] Nakayama N., Ito K., “Sprayed films of stannite Cu2ZnSnS4”, Applied Surface Science, 92(1996) 171–175.

[3] Zhou H., Hsu W.-C., Duan h.-S., Bob B., Yang W., Song T.-B., Hsu C.-J., Yang Y., “CZTS nanocrystals: a promising approach for next generation thin film photovoltaics”, Energy Environ. Sci., 6(2013)2822-2838.

[4] Catlow C.R.A., Guo Z.X., Miskufova M., Shevlin S.A., Smith A.G.H., Sokol A.A., Walsh A., Wilson D.J., Woodley S.M., Trans Phil., “REVIEW Advances in computational studies of energy materials”, R. Soc. A, (2010) 368-3379.

[5] Aron Walsh, Shiyou Chen, Su-Huai Wei, Xin-Gao Gong, “Kesterite Thin-Film Solar Cells: Advances in Materials Modelling of Cu2ZnSnS4”, Adv. Energy Mater. 2 (2012) 400–409

[6] Paier J., Asahi R., Nagoya A., Kresse G., “Cu2ZnSnS4 as a potential photovoltaic material: A hybrid Hartree-Fock density functional theory study”, Phys. Rev. B. (2009) 115-126.

[7] Ito K., Nakazawa T., “Electrical and optical properties of stannite-type quaternary semiconductor thin films,” Japanese Journal of Applied Physics, 27(1988) 2094–2097.

[8] Katagiri H., Sasaguchi N., Hando S., Hoshino S., Ohashi J., Yokota T., “Preparation and evaluation of Cu2ZnSnS4 thin films by sulfurization of e-b evaporated precursors,” Solar Energy Materials and Solar Cells, 49(1997)407–414.

[9] Wang W., Winkler M. T., Gunawan O., Gokmen T., Todorov T. K., Zhu Y., Mitzi D. B., “Device characteristics of CZTSSe thin-film solar cells with 12.6% efficiency”, Adv. Energ. Mater. 4(2014) 1301465-1301470.

[10] Tanaka K., Moritake N., Uchiki H., “Preparation of Cu2ZnSnS4 thin films by sulfurizing sol-gel deposited precursors,” Solar Energy Materials and Solar Cells, 91(2007)1199–1201.

[11] Tanaka K., Oonuki M., Moritake N., Uchiki H.., “Cu2ZnSnS4 thin film solar cells prepared by non-vacuum processing”, Sol. Energy Mater. Sol. Cells, 93 (2009)583–587.

[12] Woo K., Kim Y., Moon J., “A non-toxic, solution-processed, earth abundant absorbing layer for thin-film solar cells,” Energy & Environmental Science, 5(2012), 5340–5345.

[13] Tunuguntla V., Chen W., Shih P., Shown I., Lin Y., Lee C., Hwang J., Chen L., Chen K.H., “Nontoxic Solvent Based Sol-Gel Cu2ZnSnS4 Thin Film for High Efficiency and Scalable Low-cost Photovoltaic Cells”, J. Mater. Chem. A, 2015, DOI: 10.1039/C5TA02833G.

[14] Williamson G. K., Hall W. H., “X-ray line broadening from filed aluminium and wolfram”, Acta Metall. 1(1953) 22–31.

[15] Chun-Ran Li, Yong-Feng Li, Bin Yao, Gang Yang, Zhan-Hui Ding, Rui Liu, Lei Deng, “Electronic and optical properties of kesterite Cu2ZnSnS4 under in-plane biaxial strains: First-principles calculations”, Physics Letters A 377 (2013) 2398-2402.

[16] Tauc J., Grigorovici R., Vancu A., “Optical Properties and Electronic Structure of Amorphous Germanium”, Physica status solidi B 15 (1966) 627-629.

[17] Seo D., Lim S., “Effect of sulfur and copper amounts in sol-gel precursor solution on the growth, crystal properties, and optical properties of Cu2ZnSnS4 films”, Materials Science: Materials in Electronics, 24(2013)3756–3763.

[18] Yoo H., Kim J., Zhang L., “Sulfurization temperature effects on the growth of Cu2ZnSnS4 thin film”, Current Applied Physics, 12(2012)1052-1057.

[19] Babichuk I.S., Yukhymchuk V.O., Semenenko M.O., Klyui N.I., Caballero R., Hreshchuk O.M., Lemishko I.S., Babichuk I.V., Ganus V.O., Leon M., ”Optical and morphological properties of tetragonal Cu2ZnSnS4 thin films grown from sulphide precursors at lower temperatures”, Semiconductor physics, quantum electronics and optoelectronics, 17(2014)284-290.

[20] Maheshwari B. U., Kumar V. S., “Influence of annealing on p-type Cu2ZnSnS4 thin film by dip coating solution growth technique for the application of solar cell”, Modern Optics 61 (2014)1225-1230.