Effects of Sintering Atmosphere on the Optical, Thermal and Electrical Properties of Inkjet Printed ZnxCu(1-x)Fe2O4 Thin Films

Abstract

The effects of sintering atmosphere on the optical, thermal and electric properties of inkjet printed Zn_xCu_(1-x)Fe₂O₄ thin films have been investigated. The thin film samples were sintered separately in vacuum and oxygen. The obtained samples were then characterized by X-ray diffraction (XRD), optical band gap, electrical conductivity, Seebeck coefficient and thermal conductivity. XRD analysis showed that the fabricated samples have a cubic spinel structure of zinc copper ferrite regardless of the sintering atmosphere. The electrical conductivity of Zn_xCu_(1-x)Fe₂O₄  thin films sintered in oxygen was about 5 % higher compared to Zn_xCu_(1-x)Fe₂O₄ thin films sintered in vacuum. The optical band gap shows that the samples sintered in oxygen had smaller band gap compared to samples sintered in vacuum. The electronic band structure simulated through ABINIT shows Zn_xCu_(1-x)Fe₂O₄ is an indirect band gap material. A smaller electronic band gap was observed in O2 rich condition and was in agreement with the optical band gap and electrical conductivity test results. Seebeck coefficient of Zn_xCu_(1-x)Fe₂O₄ thin films sintered in oxygen remained positive , confirming charge transport by hole carries as p-type semiconductors. A change from p-type to n-type semiconductors was observed when Zn_xCu_(1-x)Fe₂O₄ thin films sintered in vacuum.