Interlayer effect on photoluminescence enhancement and band gap modulation in Ga-doped ZnO thin films

Nano-dimensional ZnO have drawn much attention due to its wonderful transmittance, high UV emission, better environmental and thermal stability, abundant resources and low price for use in many advanced applications. In this context, here we report photoluminescence and structural properties of Ga-doped ZnO thin films, synthesized using pulsed laser deposition. The profound effect of Au and Ag as interlayer on Ga-doped ZnO thin films has been presented systematically. The crystalline texture of the grown films was properly oriented along (002) lattice planes with hexagonal wurtzite structure as determined by X-ray diffraction analysis. Surface study was carried out by means of field emission scanning electron microscope revealing low roughness on surface of the films. These films reveal an enhancement of twofold photoluminescence behavior in the near band edge emission region with the insertion of metallic interlayer. The band gap energies of the films obtained were 3.29-3.52 eV using IR spectrophotometer. Reflectance spectra reveal less reflectance (<16%) and more absorption in the UV-NIR region which provide a novel way to replace other UV and IR photodetectors with Ga-doped ZnO.