Structure and luminescence of (Zn,Mg)O:Zn2+ nanophosphor films

A versatile homogeneous solution growth method is developed for depositing (Zn,Mg)O:Zn2+ nanophosphor films from aqueous solutions of zinc, magnesium and triethanolamine. The effect of pH on the structural and morphology of (Zn,Mg)O:Zn2+ nanophosphor films was studied and the optimum deposition conditions have been outlined. The deposition rate of nanophosphor film at neutral pH condition was comparatively larger than in basic conditions. The as-deposited films exhibit good crystallinity with hexagonal wurtzite crystalline structure and prefembly oriented along (002) plane. With time, the nanophosphor films appeared dense on the glass substrate comprising of particle sizes of 30-50 nm. Upon excitation at 326 nm, photoluminescence (PL) spectrum corresponding to deep level impurities (similar to 410-530 nm) was completely masked by the strong blue-green emission at similar to 456 nm. The ratio of Mg to Zn was optimized for maximum PL brightness whereas the optical transmittance of the nanophosphor film decreased with increasing thickness. (C) 2007 Elsevier B.V. All rights reserved.