Synthesis and Characterization of CdS/Cu₂ZnSnS₄ (CZTS) Heterojunction Thin Film for Solar Cell Applications

The CdS/Cu₂ZnSnS₄ (CZTS) heterojunction thin films successfully synthesized using Successive Ionic Layer Adsorption And Reaction (SILAR) method at room temperature over the glass substrate with the motive to characterize for solar cell applications. These as deposited thin films have been characterized for structural, compositional, morphological, optical and I-V characteristics. The X-ray diffraction (XRD) pattern analysis confirms formation of kesterite structure with tetragonal geometry; high intensity of pronounced peak associated with dominated growth oriented along (112) direction. Peaks obtained at 800 cm⁻¹, 950 cm⁻¹ and 1100 cm⁻¹ as observed from Raman spectrum also confirms kesterite CZTS structure. Surface morphology as observed shows uniform distribution of grains over the substrate surface, the optical transmittance spectrum used to calculate energy band gap, which is observed to be 2.79 eV corresponding to the exciton induced grain boundary charge transfer phenomenon. I–V characteristic shows semiconducting nature, however an increase in current voltage response is noted upon illumination to light of 100 mW/cm² (AM1.5) resulted into obtaining of 1.78% of conversion efficiency.