We collect and spectrally resolve photoluminescence from single CdSe nanocrystallite quantum dots. The elimination of spectral inhomogeneities reveals resolution limited spectral linewidths ( $<120\mathrm{}\mu \mathrm{eV}$ at 10 K) more than 50 times narrower than expected from ensemble measurements. Light driven spectral diffusion is observed as a form of power broadening. These studies confirm the atomiclike nature of the emitting state in CdSe nanocrystallites.

• Received 18 July 1996

DOI:https://doi.org/10.1103/PhysRevLett.77.3873