Effective photoabsorption of two-way spin-coated metal oxides interfacial layers: Surface microstructural and optical studies

Abstract

In this study, Molybdenum oxide (MoO3) and Vanadium oxide (V2O5) thin films were grown separately on pre-deposited cobalt oxide (Co3O4) thin film to form two different bilayer structures. The films were synthesized by spin-coating deposition technique. The precursors were prepared from common chemical reagents. Sample's surface microstructure, elemental composition and optical properties were investigated. The microstructural studies of the deposited bilayers show that the Co3O4 underlayer comprises crystalline grains with some overgrown clusters. Nanorod arrays of MoO3 adhering to the underlying Co3O4 layer with no chemical interaction are observed. In the second sample, the V2O5 top layer completely laminated the proximate Co3O4 film. Optical properties of the samples were examined from the UV/Vis spectra data. Energy band gap and band tail width changed with the adherence of top layer. Optical skin depths were also analyzed to reaffirm the suitability of the structures as potential window in thin film photovoltaics. The study demonstrated cheap process of developing interfacial layers of some transition metal oxide materials with high photoresponse. It also showed that the layers can offer the advantage of enhancing light harvesting, charge transport and storage.