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Light emission properties of nanoparticles doped with transition metal and rare earth ions

Nanoparticles of wide band gap II-VI compounds doped with transition metal (TM) and rare earth (RE) ions show fairly efficient light emission. Mechanisms of enhancement of 3d-3d (TM ions) and 4f-4f (RE ions) intra-shell transitions are discussed. It is demonstrated that quantum confinement, imposed on free carriers in nanoparticles, enhances spin dependent interactions of free carriers with TM and RE impurities. These interactions relax parity and spin selections rules for intra-shell transitions. We also show that host-to-impurity energy transfer is increased in nanoparticles, as compared to situation found in bulk samples.