Investigation on the sulfurization temperature dependent phase and defect formation of sequentially evaporated Cu-rich CZTS thin films

Choudhari, Nagabhushan J and Raviprakash, Y and Bellarmine, F and Rao, Ramachandra M S and Pinto, Richard (2020) Investigation on the sulfurization temperature dependent phase and defect formation of sequentially evaporated Cu-rich CZTS thin films. Solar Energy, 201. pp. 348-361. ISSN 0038-092X

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Abstract

We report synthesis of Copper Zinc Tin Sulfide (CZTS) thin films using sequential evaporation technique. The asdeposited films were subjected to various sulfurization temperatures ranging from 520 °C to 640 °C. This paper presents a detailed analysis of temperature dependent phase and defect formation in Cu-rich off-stoichiometric CZTS thin films. CZTS thin films moved from F-type to C-type with decreasing Cu/Zn disorder and defect concentration with increasing sulfurization temperature. The resulting films showed less off-stoichiometry in contrast to initial choice of intended off-stoichiometry exhibiting the structural flexibility within the compositional limits. Despite being off-stoichiometric, all the samples exhibited the tetragonal CZTS phase with preferred orientations. Raman analysis showed the disappearance and reappearance of secondary phases with increasing sulfurization temperature. EDS analysis suggested that composition of the films moved towards better stoichiometry till 580 °C before deteriorating again. Composition and lattice parameter values suggested Cu-rich offstoichiometric nature of sulfurized CZTS thin films. AFM study showed dependence of roughness with sulfurization temperature. Band gap was obtained in the range of 1.28 eV to 1.48 eV from UV–Vis spectroscopy measurement. PL analysis revealed the asymmetric shape and blue shift of the peaks. Band-to-tail recombination becomes pronounced with increase in sulfurization temperature. XPS analysis showed elements are in expected oxidation states

Item Type: Article
Uncontrolled Keywords: Cu2ZnSnS4 (CZTS) Solar absorber layer Sulfurization Thin film photovoltaics Off-stoichiometry Secondary phases
Subjects: Engineering > MIT Manipal > Physics
Depositing User: MIT Library
Date Deposited: 27 Jun 2020 10:33
Last Modified: 27 Jun 2020 10:33
URI: http://eprints.manipal.edu/id/eprint/155365

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