  We show that the photoluminescence emitted from a dense, two-component
ensemble of quantum dots is significantly higher than that from quantum dots of
either of the two pure systems (CdS and ZnO). The semiconductor nanocomposite,
in which the characteristic grain size of each species was 2-3 nm, was
deposited directly on Si wafers by high-pressure magnetron sputtering. It
exhibits a single, relatively sharp optical absorption edge. Further, using the
classical Young's double slit experiment we show - possibly for the first time
- that the emitted photoluminescence has significant spatio-temporal coherence,
a fact that would be crucial for their use in quantum information processing as
well as for lasing action from light-emitting particles.
