DFT and experimental investigations on ZnxCu2-xO for electronic, thermoelectric and optical applications

Semiconducting Cu₂O have excellent optical and electronic properties and are more promising candidates for advanced electronic applications. In the current study, pure and 3.125%, 6.25%, and 12.5% Zn doped Cu₂O compositions were studied using density functional theory in the framework of wien2k-code. Experimentally, uniform and smooth thin films of these compositions were successfully synthesized through the spin coating technique. The elemental composition and morphology were studied using energy-dispersive X-ray spectroscopy and field emission scanning electron microscopy, respectively. Crystallographic analysis of thin films shows a cubic phase structure having space-group 224 Pn-3m. The total density of states confirms the overlapping of states at the Fermi level for Zn-doped compositions. The significant variations in thermoelectric parameters observed with change of temperature for pure and Zn substituted Cu₂O compositions, especially the Seebeck-coefficient values vary from 2.5 × 10⁻⁴ to 5.5 × 10⁻⁵ VK⁻¹ for these cuprous oxide compositions. The optical-parameter such as absorption and extinction coefficient curves reached maxima at the highest photon energies. The enhancement in transmittance power and reduction in the band gap energy from 2.08 eV to 1.75 eV with the substitution of Zn material enhanced the availability of these compositions for advanced applications.

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