  We report an optical study of the dynamics of photoexcited carriers in Si2Te3
nanowires at various temperatures and excitation powers. Si2Te3 nanowires were
synthesized, by using gold as a catalyst, on a silicon substrate by the
chemical vapor deposition method. The photoluminescence spectrum of Si2Te3
nanowires was primary dominated by defect and surface states related emission
at both low and room temperatures. We observed that the decay time of
photoexcited carries was very long (> 10 ns) at low temperatures and became
shorter (< 2 ns) at room temperature. Further, the carrier decay time became
faster at high excitation rates. The acceleration of the photoexcited carrier
decay rates indicate the thermal quenching along with the non-radiative
recombination at high temperature and excitation power. Our results have
quantitatively elucidated decay mechanisms that are important towards
understanding and controlling of the electronic states in Si2Te3 nanostructures
for optoelectronic applications.
