The Theoretical Study Of Electronic Structure Of Semiconductor Quantum Dots

In this thesis, the electronic structures in semiconductor quantum dots (QDs) are investigated in detail using the effective-mass approximation. The aim is to explore the physical mechanisms of the new effects in low-dimensional semiconductor systems, and to supply physical models and make the theoretical validity in designing novel quantum devices with better properties.Through the calculation of the ground state energy and binding energy of the exciton in semiconductor QDs of different shape, we have studied the effects of quantum confinement and dielectric confinement on the exciton in different shape QDs. The influence of the shape and the size of QDs on an exciton is explained theoretically. The result shows the effects of the shape of QDs on excitonic states can not be neglected.We have also studied the effects of dielectric confinement on the exciton in CdSe QDs. It is found that the dielectric confinement should include two parts: one is the surface polarization effect resulted from the difference between the QDs dielectric constants and the surrounding medium dielectric constants, the other is the size effect of QDs dielectric constants. We have explicated why the calculating the ground state energy of QDs is always larger than theirs experimental results in strong confinement by the effective mass-approximation.We have calculated of the energy spectra of electron and donor in the semiconductor quantum disks of various potential shapes, both with and without external magnetic field. The binding energy of the donor impurity has also been obtained. The results show that...