In an effortlessly way, layers of manganese dioxide (MnO2) prepared at room temperature by chemical bath deposition. The thermal treatment were investigated to obtain the best control over microstructure and optical properties of manganese oxides. Determinations show that the layers structure is σ-MnO2 at room temperature after annealing transformed to Ramsdellite, Pyrolusite, and Manganite structures. From the transmittance spectra of the layers, the optical band gap obtained about 3.75 eV for the as-deposited layer, while different band gap after the thermal treatment depending on the annealing temperature. The results show annealing temperature affects optical factors similar to extinction coefficient, refractive index, and dielectric constant. Hope these finding will be useful in the future development of environmental friendly manganese oxide-based optical layers systems.
