Increasing the Photovoltaic Efficiency of Semiconductor (Cu_1−xAg_x)₂ZnSnS₄ Thin Films through Ag Content Modification

The research referred to in this study examines the morphological, structural, and optical characteristics of kesterite (Cu_1−xAg_x)₂ZnSnS₄ (CAZTS) thin films, which are produced using a process known as thermal evaporation (TE). The study’s main goal was to determine how different Ag contents affect the characteristics of CAZTS systems. X-ray diffraction (XRD) and Raman spectroscopy were used to confirm the crystal structure of the CAZTS thin films. Using a mathematical model of spectroscopic ellipsometry, the refractive index (n) represented the real part of the complex thin films, the extinction coefficient (k) portrayed the imaginary part, and the energy bandgap of the fabricated thin films was calculated. The energy bandgap is a crucial parameter for solar cell applications, as it determines the wavelength of light that the material can absorb. The energy bandgap was found to decrease from 1.74 eV to 1.55 eV with the increasing Ag content. The ITO/n-CdS/p-CAZTS/Mo heterojunction was well constructed, and the primary photovoltaic characteristics of the n-CdS/p-CAZTS junctions were examined for use in solar cells. Different Ag contents of the CAZTS layers were used to determine the dark and illumination (current–voltage) characteristics of the heterojunctions. The study’s findings collectively point to CAZTS thin layers as potential absorber materials for solar cell applications.