Band gap tailoring and raman studies of mn doped zno thin film deposited by ultrasonic spray pyrolysis

Abstract

The pristine and Mn doped ZnO thin films are deposited using low cost ultrasonic spray pyrolysis system at different temperatures (400, 450 and 500 °C). The doping concentration of Mn was varied from 2 to 20% in the film. The deposition temperature has no effect on band gap of 5% Mn doped ZnO and it is found to be *3.27 eV for different deposition temperatures. The deposition temperature is found to affect the band gap of undoped ZnO and it decreases from 3.21 to 2.93 eV with increase in deposition temperature. This is due to compressive stress relaxation in the films. The transmittance of Mn doped ZnO thin films increases in the visible region. Raman spectra shows that Mn doped ZnO has broad band in the range of 500–600 cm−1 and second order vibration is more prominent in Mn doped ZnO film with broadening of the E2 peak because of scattering geometries.