High resolution resonant photoluminescence excitation of Cd Se ∕ Zn S nanocrystals at low temperatures

We present a new technique to perform high resolution resonant photoluminescence excitation of Cd Se ∕ Zn S nanocrystals. The method takes advantage of the long photoluminescence decay times ( ∼ 1 μ s ) observed in this system at liquid helium temperatures. Resonant photoluminescence excitation can be performed using a tunable pulsed excitation and a time-gated detection. Spectral hole burning investigations on an ensemble of Cd Se ∕ Zn S nanocrystals lead to homogeneous linewidths of ∼ 100 μ eV for the band edge exciton state.