Quaternary Cu₂NiSnS₄ thin films as a solar material prepared through electrodeposition

Quaternary chalcopyrite compounds (Cu₂XSnS₄, X=Zn, Fe, Co, Ni) are promising candidate materials for thin-film solar cells because of their abundance and nontoxic compositions. Here, 1.2-μm-thick Cu₂NiSnS₄ (CNTS) thin films were successfully fabricated through electrodeposition. The structural, morphological, and optical properties of the CNTS thin films were characterized through high-resolution X-ray diffraction, field emission scanning electron microscopy, and ultraviolet-visible-near-infrared spectrophotometry. The bonding properties of CNTS was measured through Raman scattering, which revealed two principal Raman peaks of A₁ mode at approximately 280 and 350 cm^-1. The morphology of CNTS was uniform with an average grain size of 1±0.2 μm. The valences of the thin-film constituents were Cu⁺¹, Ni⁺², Sn⁺⁴, and S^-2. The optical band gap of CNTS was approximately 1.2 eV, which is suitable for thin-film photovoltaic applications.