Towards phase pure CZTS thin films by SILAR method with augmented Zn adsorption for photovoltaic applications

• Published in: Materials for renewable and sustainable energy Vol. 8; no. 3; pp. 1 - 8
• Main Authors: Krishnan, Ambily, Rishad Ali, K., Vishnu, Geetha, Kannan, Pradeesh
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.09.2019; Springer Nature B.V; SpringerOpen
• Subjects: Absorption; Absorption spectra; Absorptivity; Adsorption; Carrier density; Cations; Chemistry and Materials Science; Copper sulfides; Materials Science; Multilayers; Optical band gap; Original Paper; P-n junctions; Photovoltaics; P–N junction; Renewable and Green Energy; Resistivity; SILAR; Solar energy material; Thin films; Tin; Titanium dioxide; Zinc; Solar energy material; Optical band gap; SILAR; Resistivity; P–N junction
• ISSN: 2194-1459; 2194-1467
• DOI: 10.1007/s40243-019-0152-1

Cu 2 ZnSnS 4 (CZTS) thin films were deposited from a single cationic bath by Successive Ionic Layer Adsorption and Reaction (SILAR) method. Regular SILAR route for CZTS had the drawback of preferential adsorption of copper and tin cations in comparison with zinc. This resulted in Cu 3 SnS 4 (CTS) and Cu 2 S phases rather than phase pure CZTS films. A modified SILAR route, with a separate bath for Zn 2+ ions, circumvented the difficulty and hence led to phase pure CZTS thin films. UV–visible absorption spectra of the CZTS thin films showed absorption coefficients of ~ 10 4 cm −1 and a band gap of 1.5 eV. Combined van der Pauw and Hall measurements of CZTS thin films showed a resistivity of approximately 1.51 × 10 2 Ωcm, carrier density of ~ 1.28 × 10 17 cm −3 , and mobility ~ 0.32 cm 2 V −1 s −1 . A completely solution processed P–N junction was fabricated and characterized by forming glass/FTO/TiO 2 /CdS/CZTS multilayer.