Partially confined excitons in semiconductor nanocrystals with a finite size dielectric interface

The combined effect of finite potential barriers and the dielectric mismatch between dot and matrix on excitonic properties of semiconductor quantum dots has been studied. To avoid the unphysical divergence in the self-polarization energy which arises for the simplest and profusely adopted step-like model of the dielectric interface, we proposed a realistic (finite size) smooth profile for the dielectric interface. We have found that the excitonic binding energy can either be higher than the corresponding one to complete confinement by infinite barriers or essentially zero for a wide range of dot sizes depending on the thickness of the dielectric interface.