Excitonic effects in separate-confinement quantum-well heterostructures CdTe/(Cd,Zn)Te

Optical experiments, performed at 1.7 K, on three CdTe/(Cd,Zn)Te quantum-well separate-confinement heterostructures, reveal a type-I behavior of the 1s light-hole excitonic recombination line, although the band-to-band potential could be type II due to the strains. This behavior is explained in terms of the Coulombic interaction between the localized electrons and the light holes. Comparison between experimental and theoretical results provides a value for the strain-free relative valence-band offset: ${\mathit{q}}_{\mathit{v}}^0$≊20%.