Stark effect and polarizability in a single CdSe/ZnSe quantum dot

The quantum-confined Stark effect in a single self-assembled CdSe/ZnSe quan tum dot was studied by means of highly spatially resolved photoluminescence spectroscopy. A nanotechnological approach making use of a capacitor-like geometry enabled us to apply a well-defined lateral electric field on the q uantum dots. Stark shifts of up to 1.1 meV were obtained, which can be well fitted by a purely quadratic dependence on an electric field. In quite goo d agreement with theoretical calculations, an exciton polarizability of 4.9 x10(-3) meV/(kV/cm)(2) can be extracted, while the permanent dipole moment in the lateral direction is found to be negligible. (C) 2001 American Insti tute of Physics.