Spray Pyrolysis Synthesis of Pure and Mg-Doped Manganese Oxide Thin Films

Abstract

Pure and Mg-doped manganese oxide thin films were synthesized on heated glass substrates using the spray pyrolysis technique. The surface chemical composition was investigated by the use of X-ray photoelectron spectroscopy (XPS). Structural and morphological properties were studied by using X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic force microscopy (AFM). Optical properties were characterized by UV-visible spectroscopy. XPS spectra showed typical Mn (2p3/2), (2p1/2) and O (1s) peaks of Mn3O4 with a slight shift attributed to the formation of different chemical states of manganese. XRD analysis revealed the tetragonal phase of Mn3O4 with a preferred (211) growth orientation that improved with Mg-doping; likewise, grain size is observed to increase with the Mg doping. SEM images of Mn3O4 films showed rough surfaces composed of uniformly distributed nanograins whose size decreases with the Mg-doping. The manganese oxide films surface observed in AFM show a textured, rough and porous surface. The combination of transmittance and absorption data in the UV-visible range allowed determining the energy values of the Eg band gap (1.5–2.5 eV). The decrease of the band gap with the Mg-doping increase is attributed to the influence of the greater size of the Mg2+ ion in the manganese oxide lattice.

Influence of Mg doping on the structural and optical properties of manganese oxide (Mn2O3) nanoparticles

“…As observed from Table 2, bandgap decreases for increase in concentration of Mg upto 12 wt% and then increases for 15wt% concentration of Mg [46]. This decrease in band gap is due to larger ionic radii of Mg 2+ ions than Mn 2+ ions which decrease crystallite size [47].…”

Effect of Cobalt Doping on The Structural, Linear and Nonlinear Optical Parameters of Manganese Oxide Thin Layers

“…Then, the average crystallite size, D , and the micro‐strain, ε , were investigated using two different routes, the conventional one presented in the Scherrer equation and the Williamson‐Hall method, respectively: [ 23,24 ] $$$$\begin{equation}D{\;} = \frac{{0.9{\;}\lambda }}{{\beta {\;}cos\left( \theta \right)}}{\;}\end{equation}$$$$ $$$$\begin{equation}\varepsilon {\;} = \frac{{\beta {\;}cos{\;}\left( \theta \right){\;}}}{4}{\;}\end{equation}$$$$ $$$$\begin{equation}\beta {\;}\cos \left( \theta \right) = {\;}\varepsilon (4\sin \left( \theta \right)) + \frac{{\lambda F}}{D}\end{equation}$$$$With, λ ( Å ) the wavelength of the incident X‐ray beam of Cu Kα , θ ( rad ) the angle value of the selected diffraction peak, F shape factor (0.9), and β the full width at the half maximum FWHM ( rad ).…”

“…With, d hkl as the inter-plenary distance the h, k, and l are Miller indices and a, b, and c are the lattice parameters. Then, the average crystallite size, D, and the micro-strain, 𝜖, were investigated using two different routes, the conventional one presented in the Scherrer equation and the Williamson-Hall method, respectively: [23,24] D = 0.9 𝜆 𝛽 cos (𝜃)…”

Synergistic effects of Mg doping on TiO2 for improved toxic gas sensing performance at room temperature

“…This structural compatibility ensures that the desired properties and functionalities of TiO 2 are maintained while incorporating Mg as a dopant [25]. Preparation methods such as spray pyrolysis, chemical vapour deposition (CVD), sputtering, dip coating, and spin coating have been used to fabricate pure and Mg-doped TiO 2 thin films [26][27][28][29][30][31]. In our novel study, we used spray pyrolysis to deposit nano-crystalline TiO 2 films on a glass substrate, with and without Mg doping and investigated them for gas sensing application.…”