A. Anedda et al., LOW-TEMPERATURE TIME-RESOLVED PHOTOLUMINESCENCE OF THE 3.1 AND 4.2 EVEMISSION BANDS IN GE-DOPED SILICA, Journal of non-crystalline solids, 216, 1997, pp. 19-25
Time resolved photoluminescence (PL) has been performed on Ge-doped si
lica preform in the temperature range 10 to 295 K. Under pulsed KrF la
ser (5 eV) the well known alpha and beta emissions have been recorded
at different delays from excitation. An accurate analysis of the time
resolved spectra taken at different temperatures has shown the composi
te property of the two PL structures. At room temperature a components
(alpha(1), alpha(2)) are peaked at 4.09 and 4.26 eV with a decay lime
of about 10 ns. The peak energies of beta(1) and beta(2) components a
re calculated at 3.03 and 3.21 eV with lifetimes of 111 and 94 mu s, r
espectively. As temperature is decreased, alpha(1) and alpha(2) displa
y the normal behaviour increasing in intensity down to 125 K; on the c
ontrary, in the same temperature range, beta(1) and beta(2) undergo a
quenching of their intensities. Taking into account their mutual spect
ral characteristics, alpha(1) has been correlated to beta(1) and alpha
(2) to beta(2). The two sets of emission bands are tentatively attribu
ted to a single center stabilized in different environments of the gla
ssy matrix. (C) 1997 Elsevier Science B.V.