Extensive Study of Spin Coated CZTS Thin Film Absorbers for Photovoltaic Utilization

Jagdish Prasad, Jagavendra Yadav, Sunil Kumar, Hansraj Sharma, Mangej Singh

Abstract: In this study, we used the sol - gel spin coating method to synthesize Cu2ZnSnS4 (CZTS) absorber layers on common glass substrates. We investigated the morphological, optical, and structural characteristics of thin films. Various characterization techniques, including x - ray diffraction (XRD), Raman spectra, scanning electron microscopy (SEM), atomic force microscopy (AFM), and UV - visible spectroscopy, have been used to investigate these films. The XRD analysis revealed a kesterite phase with an intense peak at 28.35? representing the (112) plane. These samples have crystallite size around 5 nm, and lattice parameters a = b = 5.2 ? and c = 8.5 ?. A single strong peak (at 329 cm - 1) in the Raman spectrum verifies the development of a single - phase CZTS thin film. The SEM image depicts the homogeneous, compact, and dense surface morphological thin films. The AFM 3D micrographs show spike - like structures with average and root mean square (RMS) roughness of 0.146 nm and 0.203 nm. UV - Visible spectroscopy revealed the direct band gap energy of around 1.52 eV for CZTS thin films. With these characteristics, the fabricated CZTS films are suitable for absorber layers in photovoltaic utilization.

Keywords: Sol - gel, spin coating, kesterite, single phase, band gap