Jc. Seo et al., TIME-RESOLVED PHOTOINDUCED ABSORPTION SPECTROSCOPIC STUDY ON TRAPPED CARRIERS AT SEMICONDUCTOR-GLASS INTERFACES, Applied physics A: Materials science & processing, 64(5), 1997, pp. 445-449
The photoinduced absorption below the band gap of a color glass filter
doped by CdS0.4Se0.6 microcrystals was investigated by using time-res
olved differential transmittance spectroscopy. The electron trapping a
t microcrystal-glass interfaces was found to occur within less than 1
ps after photoexcitation. At low excitation energy density, the excite
d electrons are trapped at point defects distributed over the nanocrys
tal interfaces. Such electrons give rise to long-lived photoinduced ab
sorption with a lifetime of 3.2 ns. On the other hand, at high excitat
ion energy density, transient absorption with a fast (60 ps) and simul
taneously a slow decay component (3.2 ns) was observed. This short-liv
ed photoinduced absorption is attributed to the electrons trapped at t
he shallow trap states of the semiconductor-glass interfaces.