Exciton states in CdSe/ZnS core–shell quantum dots under applied electric fields

• Enlarged exciton binding energies in CdSe/ZnS core–shell quantum dots is obtained.
• The carriers distribution significantly depends on the electric field strength.
• The dipole moment significantly increases in large core structures.
• The redshift in the photoluminescence photon energy depends on the core size.

Within the effective-mass and parabolic-band approximations, the effect of the applied electric field on the exciton states in CdSe/ZnS core–shell quantum dots is investigated. Electron and hole single-particle energies as functions of the electric field are obtained by using the finite element method. The Coulomb interaction is calculated in the first-order perturbation theory, and optical absorption wavelengths of the nanocrystals with a fixed outer radius and different shell thicknesses are compared. We found that the spatial distribution of the carrier wave functions inside the heterostructure and emission spectra of the excitons can be tuned by varying the core size and the electric field strength.