@Article{cl.2026.079270,
AUTHOR = {Md. Rakib Hasan, Afrina Sharmin, Mimi Mondal, Md. Ahasan Habib, Rinku Majumder, Muhammad Shahriar Bashar, Md. Salahuddin Mina},
TITLE = {Spin-Coated Kesterite Based CZTS (Cu<sub>2</sub>ZnSnS<sub>4</sub>) Thin Films: Structural, Optical, and Compositional Analysis for Photovoltaic Applications},
JOURNAL = {Chalcogenide Letters},
VOLUME = {23},
YEAR = {2026},
NUMBER = {3},
PAGES = {--},
URL = {http://www.techscience.com/CL/v23n3/66873},
ISSN = {1584-8663},
ABSTRACT = {In this work, spin-coated Cu<sub>2</sub>ZnSnS<sub>4</sub> (CZTS) thin films with systematically varied thicknesses were investigated to understand their influence on structural, compositional, and optical properties relevant to high-performance photovoltaic applications. CZTS absorber layers were fabricated using a sol-gel spin-coating technique, which offers simplicity, low cost, and excellent thickness control, followed by annealing at 450°C under a nitrogen atmosphere to promote crystallization and phase formation. X-ray diffraction (XRD) analysis revealed that films with a thickness of approximately 608 nm exhibited the highest crystallinity and a preferred orientation along the (112) plane, indicating enhanced structural order and improved grain connectivity. Raman spectroscopy further confirmed the formation of single-phase kesterite CZTS, with no detectable secondary phases, ensuring material purity. Scanning electron microscopy (SEM) images demonstrated compact, uniform grains, while energy-dispersive X-ray spectroscopy (EDX) analysis indicated a slightly Cu-rich and Zn-poor composition, consistent with typical solution-processed CZTS films. Optical characterization using UV-Vis spectroscopy revealed strong absorption in the visible region, with absorption coefficients exceeding 10<sup>4</sup> cm<sup>−1</sup>, highlighting the material’s suitability for efficient light harvesting. The direct optical bandgap was estimated to range from 1.48 to 1.53 eV, achieving an optimal value of 1.50 ± 0.02 eV for the ten-layer film. Urbach energy values (0.57–0.78 eV) suggested the presence of defect-related localized states associated with grain boundaries and compositional variations. Overall, this work demonstrates that careful thickness optimization significantly enhances the microstructural, compositional, and optical properties of CZTS thin films, providing valuable insights for the design, fabrication, and optimization of efficient kesterite-based photovoltaic absorber layers for practical solar cell applications.},
DOI = {10.32604/cl.2026.079270}
}