Quantum Size level Structure of Colloidal CdTe Quantum Dot Nanocrystal : A Multi-band Approach

We have calculated size dependence of electronic structure of spherical quantum dots (SQDs) based on a direct semiconductor consisting of colloidal CdTe nanocrystal in a multiband effective mass approximation. The application of the multiband effective mass approximation on SQDs with spherical symmetries was performed analytically by introducing the concept of two Hilbert space tensorial product between the periodic Bloch function and the envelope orthogonal periodic function (EOPF) bases corresponding to the effect of the periodic crystals and the confinement potentials. The six-band Luttinger-Kohn (LK) holes and the one-band electron Hamiltonians are taken into account to get the electron-hole pair states as the bases in the calculation of exciton wave functions and some of their lower-state energies. The result of our calculation shows the strong size dependence of energy spectrum, coulomb energy, and exciton energy with the QD radius.