Synthesis of manganese oxide thin films deposited on different substrates via atmospheric pressure-CVD

In this study, we report the synthesis of manganese oxide (Mn_xO_y) thin films on stainless steel, silicon, and borosilicate glass substrates via atmospheric pressure chemical vapor deposition (AP-CVD) using Mn(thd)₃ and O₃ as precursor and reactive gas, respectively. Deposition was achieved at a low temperature of 300 °C under atmospheric pressure, offering a cost-effective and scalable alternative to traditional high-vacuum CVD methods. The films displayed excellent adhesion and reproducibility, with substrate-dependent variations in film coloration, crystal phases, and morphology. X-ray diffraction (XRD) and Raman spectroscopy confirmed the presence of Mn₃O₄ and Mn₂O₃ phases, with Mn₃O₄ predominating on stainless steel and silicon, while Mn₂O₃ was more prominent on glass. Scanning electron microscopy (SEM) revealed granular structures with uniform grain sizes, particularly on stainless steel substrates. X-ray photoelectron spectroscopy (XPS) confirmed Mn²⁺ and Mn³⁺ oxidation states, consistent with the phase distribution observed by XRD and Raman analysis. This work demonstrates the potential of AP-CVD for scalable manganese oxide thin-film synthesis, particularly for energy storage applications, where Mn₃O₄ and Mn₂O₃ can serve as precursors to δ-MnO₂ in supercapacitors. The method's simplicity, combined with the high-quality films produced, makes it a promising approach for future research and industrial-scale applications.