Role of micro-strain and defects on band-gap, fluorescence in near white light emitting Sr doped ZnO nanorods

We report tunable band gap (red shift in band gap) of ZnO driven by the Sr doping. It is observed that enhanced white light like luminescence from Sr doped ZnO nanorods. Raman studies have carried out to get insight of phonon related vibrational properties. Dopant induced local vibrational mode appeared after Sr incorporation has been identified from Raman studies. Photoluminescence studies show that doped ZnO nanorods fluorescence covers the entire visible region apart from the characteristic exciton related UV luminescence. Crystallite size variation, defects formation, and relaxation of micro strain after doping shows a strong dependence on the luminescence of the prepared samples. The increase in luminescence with increasing dopant concentration is attributed to doping induced changes in crystallinity, micro strain, and defects formation in the samples. (C) 2014 AIP Publishing LLC.