PHOTOLUMINESCENCE OF SINGLE SEMICONDUCTOR NANOCRYSTALLITES BY 2-PHOTON EXCITATION MICROSCOPY

Precise knowledge of the properties of semiconductor nanocrystallites (NCs) may determine their use in future optical devices. However, sinc e synthesis methods are not able to yield perfectly homogeneous NCs, s pectral and dynamic responses are usually averaged properties. We exam ine single NCs using two-photon microscopy and obtain narrow luminesce nce linewidths (15 meV in 55 Angstrom CdS). This technique should be b roadly applicable to single molecule spectroscopy and local probing of buried interfaces, such as quantum wells.