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Free keywords:
phonons
plasmons
ultrafast phenomena
Abstract:
Carrier and lattice dynamics of laser excited CdTe was studied by time-resolved reflectivity
for excitation fluences spanning about three orders of magnitude, from 0.064 to 6.14 mJ cm−2
.
At fluences below 1 mJ cm−2
the transient reflectivity is dominated by the dynamics of hybrid
phonon–plasmon modes. At fluences above 1 mJ cm−2
the time-dependent reflectivity curves
show a complex interplay between band-gap renormalization, band filling, carrier dynamics
and recombination. A framework that accounts for such complex dynamics is presented and
used to model the time-dependent reflectivity data. This model suggests that the excess energy
of the laser-excited hot carriers is reduced much more efficiently by emitting hybrid
phonon–plasmon modes rather than bare longitudinal optical phonons.
