Sensitization of Er luminescence by Si nanoclusters

Abstract

Sensitization of Er emission by Si nanoclusters (Si-nc) is investigated with pulsed and continuous optical pumping, in and off resonance with excited states of ${\text{Er}}^{3+}$ ion. We show that under high-power pulsed pumping, the excitation process is limited by the finite energy transfer time from Si-nc to ${\text{Er}}^{3+}$ ions. By comparison between pulsed and steady-state excitation, the concentration of sensitizers and average number of ${\text{Er}}^{3+}$ ions coupled to a single nanocluster are independently determined in an experiment. The results clarify conditions needed for efficient sensitization of ${\text{SiO}}_2:\text{Er}$ by Si-nc.