Study of Optoelectronic Properties and Density Functional Theory of Kesterite Cu2ZnSnS4 Thin Film Grown by Facile Solution Growth Technique
Abstract
Facile solution growth technique was implemented to deposit nanostructured Cu2ZnSnS4 (CZTS) kesterite thin film onto a glass substrate. AR grade Zinc Sulfate, Copper Sulfate, Tin sulfate and Thiourea were used to prepare the precursor solutions. As-grown CZTS thin film was characterized to study its structural, optical and electrical properties. The kesterite structure of the CZTS thin film has been confirmed from the X-Ray diffraction pattern. The calculated lattice parameters are in good agreement with the Standard reported values. The optical properties show kesterite CZTS film have higher absorption in the visible region. The band gap energy was obtained from the Tauc’s plot which was found to be ~1.7 eV, which lies in the range where solar spectrum has higher irradiance results in higher absorption of light. Theoretical band structure was obtained through DFT calculations based on GGA approximation which shows the direct band gap around ~0.6 eV. I-V measurements have been performed in dark and under illumination of light which resulted in high photocurrent in dark as well as under light illumination. The photosensitivity and photoresponsivity were calculated and found to be ~60 % and 70 µA/W, proves its promising candidature for solar cells.