QUANTUM-CONFINED STARK-EFFECT IN SINGLE CDSE NANOCRYSTALLITE QUANTUM DOTS

The quantum-confined Stark effect in single cadmium selenide (CdSe) na nocrystallite quantum dots was studied. The electric field dependence of the single-dot spectrum is characterized by a highly polarizable ex cited state (similar to 10(5) cubic angstroms, compared to typical mol ecular values of order 10 to 100 cubic angstroms), in the presence of randomly oriented local electric fields that change over time. These l ocal fields result in spontaneous spectral diffusion and contribute to ensemble inhomogeneous broadening. Stark shifts of the lowest excited state more than two orders of magnitude larger than the linewidth wer e observed, suggesting the potential use of these dots in electro-opti c modulation devices.