  As grown ZnO:Si nanocomposites of different compositional ratios were
fabricated by thermal evaporation techniques. These films were subjected to
post deposition annealing under high vacuum at a temperature of $\rm 250C^o$
for 90min. The photoluminescence (PL) spectra of annealed samples have shown
marked improvements both in terms of intensity and broadening. For the first
time in ZnO:Si nanocomposite films we see huge UV, red and orange peaks at 310,
570 and 640nm. Structural and Raman analysis show formation of a Zn-Si-O shell
around ZnO nano clusters wherein on heating $\rm Zn_2SiO_4$ compound forms. The
new emissions are due to $\rm Zn_2SiO_4$ which completes white light spectrum.
