  The temperature-dependent photoluminescence (PL) spectra of zinc oxide (ZnO)
nanocrystals deposited inside the ultraviolet (UV) opal were studied. ZnO was
grown in the voids between FCC packed silicon dioxide spheres using spray
pyrolysis under ultrasonic vibration in the solution containing a zinc nitrate
precursor. The ZnO nanoparticles inside opal matrix with UV photonic band-gap
exhibit suppression of the excitonic emission and enhancement of the deep level
emission. Suppression of the excitonic lines is due to the inhibition of
spontaneous emission, while enhancement and broadening of the DL emission in
the green spectral region is due to Purcell effect. The infiltration of ZnO
inside the photonic crystal may be a useful technique to increase its emission
efficiency in the selected spectral region.
