Elaboration and Characterization of Cu_2ZnSnS_4 (CZTS) Absorber Layer by Sol Gel Method for Solar Cells Applications

摘要

In this paper, we study the effect of annealing time on the structural, optical and electrical properties of elaborated Cu2ZnSnS4 (CZTS) thin films using low cost sol gel method associated to spin coating technique. The sol gel CZTS solution was deposited on ordinary glass substrates and annealed at 300 degrees C using different durations: 5 min, 10 min and 15 min. Then, the samples are analyzed using X-ray diffract-meter, UV-VIS spectrophotometer and four point probe. The obtained results show that the CZTS thin films crystalize in Kesterite structure with a preferential orientation along (112) plane. The optical parameters such as refractive index (n), extinction coefficient (k), absorption coefficient (alpha), band gap energy (E-g) real (epsilon(r)) and imaginary (epsilon(i)) part of dielectric constants have been calculated from the transmittance/absorbance data in the wavelength ranging from 350 to 1000 nm, and the estimated gap energy is between 1.51 and 1.84 eV. The obtained electrical resistivity is between 0.30 and 0.49 Omega.cm, which means a good conductivity and suitable films for photovoltaic applications.