Bond length controlling opto-structural properties of Mn doped CuO thin films: An experimental and theoretical study

Abstract

In this paper, we present a detailed study of the opto-structural properties of Mn doped CuO (MCO) thin films with 0.0, 2.0, 4.0, 6.0 and 8.0 at.% doping concentrations, using a thermal spray pyrolysis technique as well as Density Functional Theory (DFT) calculations for the first time. The experimental characterizations are done through Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-rays spectroscopy (EDX), X-ray diffraction (XRD), UV–Visible spectroscopy (UV–Vis) and Hall Effect measurement. FESEM images show the petal-like and closed packed flower-like spherical structure surface morphology. EDAX spectra confirm the presence of Cu, O and Mn atoms. The XRD pattern reveals that synthesize thin films have a monoclinic structure with some impurity phases. The estimation of crystallite size ranging from 17.11 to 31.96 nm observed using Debye-Scherrer and Halder-Wagner method. The Cu–O bond length is found consistent between the Rietveld refinement and DFT function, which controls the experimental optical band gap in between 3.00 to 2.31 eV. Further, a standard value of Urbach energy, steepness parameter, electron–phonon interaction, refractive index, dielectric constant and static dielectric constant is found in 4.0 at. % Mn dopant. Moreover, p to n-type conductivity is confirmed by 4.0 at. % Mn concentration. By a meticulous analysis, it is observed that 4.0 at. % of MCO thin films might have a potential application in electronic and optoelectronic device industry.