Vol.:(0123456789) 1 3 Journal of Materials Science: Materials in Electronics https://doi.org/10.1007/s10854-019-01676-4 Characteristics of kesterite CZTS thin flms deposited by dip‑coating technique for solar cells applications Ahmed Ziti 1,5  · Bouchaib Hartiti 1  · Hicham Labrim 2  · Salah Fadili 1  · Abdelkrim Batan 1,3  · Mounia Tahri 4  · Abderraouf Ridah 5  · Omar Mounkachi 6  · Abdelilah Benyoussef 7  · Philippe Thevenin 8 Received: 1 March 2019 / Accepted: 10 June 2019 © Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract In this work, we synthesis Cu 2 ZnSnS 4 (CZTS) thin flms by sol–gel method associated to dip-coating technique on the ordi- nary glass substrates. We investigated the efect of dip-coating speed on the structural, morphological, optical and electrical properties of flms at various speeds 30, 40, 50 and 60 mm/min, respectively. The flms have been characterized by diferent characterization techniques such as: X-ray difraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), UV–Visible spectrophotometer and four point probe method. XRD spectra showed pure kesterite CZTS with a preferential orientation along (112) plane. Raman scattering measurement showed the peak at 332 cm −1 correspond to pure CZTS phase. XPS analysis confrmed the presence of Cu, Zn, Sn and S elements on the surface of deposited CZTS. SEM images showed an improvement in density and uniformity with increasing dip-coating speed. The band gap energy is decreased with increasing of dip-coating speed in the range of 1.38–1.45 eV. The electrical conductivity increased between 4.90 and 5.81 (Ω.cm) −1 . These characteristics make the deposited CZTS flm a suitable material as an absorber layer in photovoltaic devices. 1 Introduction The semiconductors compounds such as CdTe, CuIn (S,Se) 2 , CuInGa (S,Se) 2 , CuO and Cu 2 ZnSn (S,Se) 4 are applied as absorber layers in thin flms solar cells [1–3]. Among these compounds copper zinc tin sulphur CZTS attract serious attention in the last years because of their desirable proper- ties for solar cells applications including: high absorption coefcient of 10 4 cm −1 , p type semiconductor and favour- able band gap in the range between 1.4 and 1.5 eV [4]. This optical band gap energy is very close to the desired one for an absorber layer of solar cells according to theoretical limit achieved by Shockley-Quessier for single junction cell based CZTS thin flm (~ 32%) [5]. CZTS thin flm was derivative from CIGS thin flm by changing indium by zinc and gallium by tin because of Zn and Sn are non-toxic and abundant met- als in the earth’s crust compared to rare elements including In and Ga. Ito and Nakazawa achieved the fabrication of the frst CZTS solar cells elaborated by atom beam sputtering method, the solar cells based CZTS thin flms showed an open circuit voltage of 165 mV under irradiation of AM 1.5 and gap energy estimated to 1.45 eV for CZTS thin flms. The power conversion efciency (PCE) of solar cells based on CZTS thin flms was encouraging from 2.6% in 2001 to 11% in 2012 [6, 7]. An important development in the PCE of Cu 2 ZnSn(S,Se) 4 solar cells over 12.6% has been reported via hydrazine pure solution process [8]. However this pro- cess is reactive solvent and highly toxic which makes this approach very difcult to apply up to photovoltaic industry * Ahmed Ziti ziti.ahmed91@gmail.com 1 ERDyS Laboratory, MEEM & DD Group, Hassan II University of Casablanca, FSTM, BP 146, 20650 Mohammedia, Morocco 2 Materials Science Unit/DERS/CNESTEN, Rabat, Morocco 3 Department of Chemistry, Equipe Sciences des Matériaux, FST Errachidia, University Moulay Ismail, BP509, Boutalamine, 52000 Errachidia, Morocco 4 UGPC, DSTE/DERS//CNESTEN, Rabat, Morocco 5 LIMAT Laboratory, Department of Physics FSB, Hassan II University of Casablanca, B.P.7955, Casablanca, Morocco 6 LAMCSCI, Faculty of Sciences, Mohammed V University, B.P.1014, Rabat, Morocco 7 Institute of Nanozmaterials and Nanotechnology, MAScIR, Rabat, Morocco 8 University of Lorraine, LMOPS, Metz, France