Intersubband absorption with different sublevel couplings in [(CdS/ZnSe/BeTe)/(ZnSe/BeTe)] double quantum wells

摘要

The authors demonstrated the strong sublevel coupling on the intersubband absorption at telecommunication wavelengths in asymmetric Ⅱ-Ⅵ double quantum wells consisting of a deep CdS well and a shallow ZnSe well coupled by a 1-monolayer-thick BeTe barrier. With increasing ZnSe well thickness, the sublevel coupling between excited states first increases to a maximum and then decreases, which results in a transition energy anticrossing and a reverse intensity evolution for e1-e2 and e1-e3 transitions. These results are in good agreement with the self-consistent Schroedinger-Poisson calculation. For optical switch applications, the sublevel-coupling-dependent relaxation time could be increased to lower the switching energy.