Probing the dynamics of photoexcited carriers in Si2Te3 nanowires

Abstract

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 primarily dominated by defects and surface states related emission at both low temperatures and room temperature. We observed that the decay time of photoexcited carriers 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 indicates thermal quenching and structural modification along with the non-radiative recombination at high temperatures and excitation powers. Our results have quantitatively elucidated decay mechanisms that are important toward understanding and controlling the electronic states in Si2Te3 nanostructures for optoelectronic applications.