Ga. Torchia et al., REDISTRIBUTION OF CR3-CR CRYSTALS( IONS FROM LI+ TO NB5+ SITES IN ZNOCODOPED LINBO3), Chemical physics letters, 288(1), 1998, pp. 65-70
This Letter reports on the optical spectroscopy properties of Cr3+ ion
s in codoped ZnO:LiNbO3:Cr crystals. Experimental techniques such as o
ptical absorption, luminescence, time-resolved spectroscopy and electr
on paramagnetic resonance have been used to investigate the site occup
ied by the Cr3+ ions. Two Cr3+ centres located in Li+ and Nb5+ sites (
Cr-LI(3+) and Cr-Nb(3+) centres, respectively) were observed, dependin
g on its relative concentrations of the ZnO content in the samples. Fo
r ZnO concentrations below 4.7%, the majority of centres correspond to
Cr-Li(3+) centres, whereas, for a ZnO concentration above this thresh
old both centres coexist, but with the Cr-Nb(3+) centres being more pr
edominant. The emission bands, excitation spectra and lifetimes associ
ated with both centres are reported. (C) 1998 Elsevier Science B.V. Al
l rights reserved.