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Raman mapping analysis for removal of surface secondary phases of CZTS films using chemical etching / Trystan, Watson; Wing Chung, Tsoi

Applied Physics Letters, Volume: 109, Issue: 12, Start page: 123902

Swansesa University Authors: Trystan, Watson, Wing Chung, Tsoi

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DOI (Published version): 10.1063/1.4963134

Abstract

Raman spectroscopy has been widely used as a non-destructive surface characterization method for the Cu 2ZnSnS4 (CZTS) thin films. Secondary phases, which often co-exist with CZTS, are detrimental to the device performance. In this work, removal of the secondary phases using sodium sulfide (Na 2S) a...

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Published in: Applied Physics Letters
ISSN: 1077-3118
Published: 2016
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URI: https://cronfa.swan.ac.uk/Record/cronfa29850
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Abstract: Raman spectroscopy has been widely used as a non-destructive surface characterization method for the Cu 2ZnSnS4 (CZTS) thin films. Secondary phases, which often co-exist with CZTS, are detrimental to the device performance. In this work, removal of the secondary phases using sodium sulfide (Na 2S) aqueous solution etching in various time durations was investigated. Raman scattering mapping provides a direct visualization of phase distribution in CZTS-based materials on a relatively large scale (1 mm × 10 mm). Both as-grown and etched CZTS absorber layers were examined by Raman spectroscopy with a 532 nm excitation laser light in the range of 50–500 cm-1. A clear reduction of the secondary phases (mainly SnS) at the surface after etching was confirmed by Raman spectroscopy and scanning electron microscopy. Room temperature photoluminescence (PL) reveals a pronounced correlation between the amount of secondary phases and photoluminescence peak position. The PL spectra of the regions with more Sn-rich secondary phases show clearly a shift to high wavelength of the peak position, in comparison with regions with less Sn-rich secondary phases. These observed PL changes could be due to Sn-rich defects which may cause recombination processes.
College: College of Engineering
Issue: 12
Start Page: 123902