Structural and optical properties of Cu2ZnSnS4 thin films fabricated by chemical spray pyrolysis

Abstract

Cu2ZnSnS4 (CZTS) absorber Layer fabricated by using chemical spray pyrolysis method as a fast, cheap and vacuum-free. The films have been deposited on preheated glass substrates at 400°C and thickness of about (400 nm) measured by gravimetric method. The structural, morphological, optical and electrical properties of all films have been investigated using XRD, Raman spectroscopy, Atomic Force Microscope (AFM), UV-Vis-NIR spectroscopy and Hall measurement. The crystallite size of the prepared films was estimated using Scherer's formula, the maximum crystallite size of (22.44nm) at concentration ratio (Cu/Zn+Sn=1.3M) which related to CZTSE. Raman shift measurement of the CZTS thin films showed that the main peaks located at (330-335 cm−1). The UV-Vis-NIR absorbance spectra were recorded in the region of (350-900) nm to investigate the optical characteristics. The results have shown that the optical energy gap for allowed direct electronic transition was (1.55-2.31) eV with a high absorption coefficient (α >104 cm−1) wich is suitable for solar cell applications. The Hall measurement found that maximum conductivity of (3.1017Ω.cm)−1 at concentration ratio (Cu/Zn+Sn= 1.1 M) which is related to CZTSD thin film.