Optical, structural and electrical properties of ZnO thin films doped with Mn

Abstract

Manganese-doped zinc oxide (Mn-doped ZnO) thin films were synthesized on soda lime glass substrates using the spray pyrolysis technique at substrates temperatures of 400, 450 and 500 °C. Compositional, optical, structural, morphological and electrical properties were studied with Rutherford Backscattering Spectrometry (RBS), Ultraviolet and Visible Spectroscopy (UVS), X-Ray Diffraction (XRD) analysis, Scanning Electron Microscopy (SEM) and the Four Point method, respectively. Mn-doped ZnO films show changes in transmittance and energy band gap when substrate temperature is increased. In the same way, electrical resistivity measurements show changes with temperature, getting a minimum value at 450 °C. The results were also compared with undoped ZnO thin films. They show that constant lattices, crystallite size and resistivity increase with Mn doping. These variations are the result of the substitution of Zn by Mn ions during the incorporation of Mn ions in the ZnO lattice. On the other hand, energy band gap values decrease when the samples were doped with Mn, due to the s–d and p–d exchange interactions.