Growth and characterization of pure stannite Cu2MnSnS4 thin films deposited by dip-coating technique

Semiconductor compounds Cu2MnSnS4 absorbers materials were synthesis by the sol–gel approach and deposited using dip-coating technique on ordinary glass substrates. In this work, we have studied the effect of various annealing temperature such as: 400 °C, 425 °C, 450 °C and 475 °C for 1 min on the structural, compositional, morphological, optical and electrical investigations. CMnTS thin films have been characterized by some analyse techniques such as: X-ray diffractometer (XRD), Raman spectroscopy, dispersive X-ray spectroscopy (EDS), scanning electron microscope (SEM), UV–visible spectroscopy and four-point probe method. XRD data proved the formation of stannite Cu2MnSnS4 with privileged direction at (112) plane. Crystallite size of stannite CMnTS thin films increased with the increase of annealing temperature from 7.26 to 11.57 nm with annealing temperature augmented. Raman experiments complete the confirmation of stannite CMnTS thin films existence by Raman vibrational modes located at 288 cm−1 and 330 cm−1. EDS analysis demonstrated close-stoichiometry of CMnTS thin films annealed at 450 and 475 °C. SEM images demonstrated the improvement of crystallinity and uniformity of surface morphologies when annealing temperature is 475 °C. UV–visible spectroscopy indicated that the transmittance spectra increased when annealing temperature increased in the wavelength range of 450–850 nm. The absorption coefficient values are higher than 104 cm−1, the approximated bandgap of CMnTS absorber material decrease in the range of 1.72–1.5 eV when annealing temperature increased. The electrical resistivity of CMnTS thin films decrease from 4.77 to 0.85 (Ω.cm). These properties are appropriate for photovoltaic solar cells applications.