Structural and Optical Properties of N and Mn co-doped ZnO Thin Films Grown by Ultrasonic Spray Pyrolysis Method

Nanocrystaline Nitrogene-Manganese co-doped ZnO thin films with different percentages of Mn content from 0 up to 11 at% and fixed N doped at 21 at%; were elaborated by ultrasonic spray pyrolysis a simple, cheap, and versatile method, at atmospheric pressure and a substrate temperature of 350 degrees C. We investigated the structural and optical properties of N-Mn co-doped ZnO thin films. The micro-structure of the as-prepared thin films was investigated by X-ray diffraction (XRD), FT-infrared absorption spectroscopy (FTIR) and Raman scattering spectroscopy. The XRD patterns of all samples reveal the presence of a single hexagonal wurtzite phase structure. The grain size decreases from 52 to 23 nm. FTIR confirms the incorporation of Mn atoms in the ZnON matrix without any extra-absorption bands due to Mn oxides. The Mn incorporation effect, in ZnO matrix is clearly evidence by the apparition of the peaks around 528 cm(-1). UV-Vis-NIR spectroscopy shows that the optical band gap energy increases (i.e., Blue-shift), with Mn-doping content which leads to the optical phonon confinement and/or to the Burstein-Moss effect. Finally, all our nanocrystalline thin films are very homogeneous in the chemical contents and Mn is uniformly incorporated into the hexagonal wurtzite structure by substituting Zn atoms without any phase segregation.