Surface Characterisation of Spin Coated Quaternary Chalcogenide CZT(S, O) Thin Film for Optoelectronic Applications

Abstract

Thin films of copper zinc tin sulphide (CZTS) have been deposited on glass substrate at various solution concentration and angular speed using sol-gel spin coating technique. Surface morphology showed that the deposited layers are continuous and pinhole free. The film’s particles are evenly distributed and adhered firmly to the substrates. X-ray diffraction studies revealed that the films are polycrystalline with tetragonal kesterite structure. Interplanar spacing and average crystallite size were estimated as 3.732 A and 56.53 nm. Film’s thickness and stoichiometry were determined from Rutherford Backscattering Spectroscopy (RBS) as127 nm and Cu1.5Zn1.0Sn1.1S4.4O3.3. Optical studies showed that the deposited films exhibit direct band transition. The values of the energy gap were found between 1.30 and 1.60 eV. The result of the study suggested that the deposited CZTS thin films can perform as a good absorber material in nanostructured optoelectronic devices.