IMPACT OF SELENIZATION TEMPERATURE AND PRE-ANNEALING TREATMENT ON THE MICROSTRUCTURAL PROPERTIES OF Cu2ZnSnSe4 THIN FILMS GROWN BY RAPID THERMAL PROCESS

Abstract

The impact of selenization temperature and pre-annealing treatment on the microstructural characteristics of CZTSe thin films were studied. CZTSe thin films were obtained by two-stage process. This processes includes deposition of metallic layers and Se cap layer employing physical vapor deposition systems followed by selenization process performed at elevated temperatures using RTP system with a heating rate of 8°C/s. The compositional properties of CZTSe thin films changed after the heat treatment, but performing pre-annealing treatment before high reaction temperature (550°C) partially prevented element loss in CZTSe compound. Both Raman and XRD measurements confirmed the formation of the kesterite CZTSe phase. However, according to Raman results, CZTSe phase started to decompose into secondary phases such as CTS regardless of temperature. According to the top view images of the samples, the grain structure completely changed with employing heat treatment. Zn-rich phase detected in reacted sample at 550 °C, which indicates decomposition of CZTSe that is confirmed in Raman spectra.

Keywords

• CZTSe thin film
• RTP
• XRD
• Microstructure

References

1. I. Dudchak, L. J. J. o. a. Piskach, and compounds, "Phase equilibria in the Cu2SnSe3–SnSe2–ZnSe system," vol. 351, no. 1-2, pp. 145-150, 2003.
2. J. J. Scragg, P. J. Dale, D. Colombara, and L. M. J. C. Peter, "Thermodynamic aspects of the synthesis of thin‐film materials for solar cells," vol. 13, no. 12, pp. 3035-3046, 2012.
3. A. Redinger et al., "Route Toward High-Efficiency Single-Phase Cu $ _ {\bf 2} $ ZnSn (S, Se) $ _ {\bf 4} $ Thin-Film Solar Cells: Model Experiments and Literature Review," vol. 1, no. 2, pp. 200-206, 2011.
4. P. Fan et al., "Effects of annealing treatment on the properties of CZTSe thin films deposited by RF-magnetron sputtering," vol. 625, pp. 171-174, 2015.
5. P. Salomé, P. Fernandes, and A. d. J. p. s. s. c. Cunha, "Influence of selenization pressure on the growth of Cu2ZnSnSe4 films from stacked metallic layers," vol. 7, no. 3‐4, pp. 913-916, 2010.
6. H. Yoo and J. J. T. S. F. Kim, "Growth of Cu2ZnSnS4 thin films using sulfurization of stacked metallic films," vol. 518, no. 22, pp. 6567-6572, 2010.
7. M. J. S. Olgar and Microstructures, "Optimization of sulfurization time and temperature for fabrication of Cu2ZnSnS4 (CZTS) thin films," vol. 126, pp. 32-41, 2019.
8. M. Olgar, A. Sarp, A. Seyhan, and R. J. R. E. Zan, "Impact of stacking order and annealing temperature on properties of CZTS thin films and solar cell performance," vol. 179, pp. 1865-1874, 2021.

9. J. Márquez-Prieto et al., "Impact of the selenisation temperature on the structural and optical properties of CZTSe absorbers," vol. 152, pp. 42-50, 2016.
10. V. Kumar, A. Dutta, U. P. J. S. Singh, and Microstructures, "Optimization of selenization parameters for fabrication of CZTSe thin film," vol. 144, p. 106578, 2020.
11. S. van Duren et al., "Pre-annealing of metal stack precursors and its beneficial effect on kesterite absorber properties and device performance," vol. 185, pp. 226-232, 2018.
12. M. Arasimowicz, M. Thevenin, and P. J. J. M. O. P. L. Dale, "The effect of soft pre-annealing of differently stacked Cu-Sn-Zn precursors on the quality of Cu2ZnSnSe4 absorbers," vol. 1538, pp. 123-129, 2013.
13. M. A. Olgar et al., "Effect of heat treating metallic constituents on the properties of Cu2ZnSnSe4 thin films formed by a two-stage process," vol. 624, pp. 167-174, 2017.
14. S. Chen, A. Walsh, X. G. Gong, and S. H. J. A. m. Wei, "Classification of lattice defects in the kesterite Cu2ZnSnS4 and Cu2ZnSnSe4 earth‐abundant solar cell absorbers," vol. 25, no. 11, pp. 1522-1539, 2013.
15. J. J. Scragg, T. Ericson, T. Kubart, M. Edoff, and C. J. C. o. M. Platzer-Bjorkman, "Chemical insights into the instability of Cu2ZnSnS4 films during annealing," vol. 23, no. 20, pp. 4625-4633, 2011.
16. D. R. Lide, CRC handbook of chemistry and physics. CRC press, 2004.
17. M. A. Olgar et al., "Influence of copper composition and reaction temperature on the properties of CZTSe thin films," vol. 682, pp. 610-617, 2016.
18. A. J. P. r. Patterson, "The Scherrer formula for X-ray particle size determination," vol. 56, no. 10, p. 978, 1939.
19. D. Santos-Cruz, S. Mayén-Hernández, F. de Moure-Flores, J. Campos-Álvarez, M. Pal, and J. J. R. i. p. Santos-Cruz, "CuOX thin films by direct oxidation of Cu films deposited by physical vapor deposition," vol. 7, pp. 4140-4144, 2017.