Energy levels of CdSe quantum dots: Wurtzite versus zinc-blende structure

A simple tight-binding model is used to calculate the energy levels of CdSe quantum dots for two distinct crystal structures: the wurtzite and the zinc-blende structure. Comparison of both level schemes gives an estimate of the shift in energies due to the interior bonding geometry of the lattice structure. Our model makes allowance for the valence-band degeneracy, a finite barrier at the dot boundary, and the full electron-hole interaction. Also calculated are the oscillator strengths of the dipole-allowed transitions. All results are compared with recent experimental findings.