Structural optical and electronic properties of Fe and Ga doped ZnO thin films grown using pulsed laser deposition technique

Band gap engineering in ZnO thin films have been subject of intensive studies. The thin films of 2 wt % Fe and 2 wt % Ga doped ZnO and undoped ZnO were deposited on glass substrate by pulse laser deposition technique. Structural, optical and electronic structure properties of these thin films were investigated by X- Ray diffraction (XRD), UV-Vis spectroscopy and X-ray absorption spectroscopy (XAS), respectively. XRD studies show that all the thin films are highly oriented along the c-axis and maintain the wurtzite structure. Out of plane lattice parameter in Ga doped is smaller while in Fe doped is larger, compared to undoped ZnO. The band gaps of doped films have been found to increase due to doping of the Ga and Fe ions. XAS studies across O K edges of doped thin films show that the conduction band edge structure probed via oxygen 1s to 2p transitions have modified significantly in Ga doped sample.