GEOMETRICAL EFFECTS ON THE GROUND-STATE ENERGY OF HYDROGENIC IMPURITIES IN QUANTUM DOTS

The effect of non-sphericity of quantum dots on the ground state energ y of hydrogenic impurities is studied in the frame of the effective ma ss approximation (EMA) and the variational method. The difference in c omposition of the quantum dot and the host material is modeled with a potential barrier at the boundary of the dot. To make the analysis, we have considered two symmetries for the quantum dot: spherical and sph eroidal. In this way, the ground state energy is calculated as a funct ion of the volume of the quantum dot, for different barrier heights. T he results show that the ground state is strongly influenced by the ge ometry of the dot, that is, for a given volume and barrier height, the energy is clearly different if the dot is spherical or spheroidal in shape when the volume of the dot is small (strong confinement regime). As the volume of the dot increases (weak confinement regime) the geom etry becomes irrelevant, as expected.