  Correlative light and electron microscopy promises to combine molecular
specificity with nanoscale imaging resolution. However, there are substantial
technical challenges including reliable co-registration of optical and electron
images, and rapid optical signal degradation under electron beam irradiation.
Here, we introduce a new approach to solve these problems: multi-color imaging
of stable optical cathodoluminescence emitted in a scanning electron microscope
by nanoparticles with controllable surface chemistry. We demonstrate
well-correlated cathodoluminescence and secondary electron images using three
species of semiconductor nanoparticles that contain defects providing stable,
spectrally-distinguishable cathodoluminescence. We also demonstrate reliable
surface functionalization of the particles. The results pave the way for the
use of such nanoparticles for targeted labeling of surfaces to provide
nanoscale mapping of molecular composition, indicated by cathodoluminescence
color, simultaneously acquired with structural electron images in a single
instrument.
