Effect of Ni incorporation on structural, optical, morphological properties of ZnO thin films deposited by laser ablation

The structural, optical and morphological properties of Ni-doped ZnO (NZO) thin films were studied by X-ray diffraction (XRD), ultraviolet-visible absorbance spectroscopy (UV-Vis), Photoluminescence spectroscopy (PL), atomic force microscopy (AFM), Field emission scanning electron spectroscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). 0%, 3%, 5%, and 7% NZO thin films were deposited on fused silica substrate by pulsed laser deposition (PLD) technique at a substrate temperature of 300 oC at oxygen partial pressure of 1 mTorr. XRD results show that all deposited films were crystalline and oriented along (002) plane with wurtzite symmetry. All deposited films also show high transmittance in the UV-Visible region (300-800 nm) and their band gaps were calculated using Tauc's formulation. NZO thin films show a lesser bandgap i.e. 3.20 eV for 3% and 3.11 eV for 7% Ni doped ZnO film as compared to pure ZnO films. Photoluminescence shows emission in the visible region at 430 nm. AFM and FESEM results revealed the uniform deposition of NZO and ZnO films over a fused silica substrate and FTIR analysis shows the shifting of Zn-O-Zn band towards higher wavenumber region with different Ni concentrations. Results obtained from this study indicate that NZO thin films grown by PLD technique can be a promising candidate for optoelectronic application.