Theory for quantum-dot quantum wells: Pair correlation and internal quantum confinement in nanoheterostructures

Spherical quantum-dot–quantum-well nanocrystallites, with internal radial quantum-well band profiles, can now be fabricated. Pair states in these nanoheterostructures are determined by electron-hole attraction, global confinement in the dot, and local confinement within the well. Configuration-interaction calculations using effective-mass models with screened pair interaction give accurate exciton energies for CdS/HgS quantum-dot quantum wells. Binding energy and pair correlation are suppressed but pair-oscillator strengths are enhanced by adding a HgS quantum well to a CdS quantum dot.