Shorter wavelength intersubband absorption down to λ = 1.55 µm in (CdS/ZnSe)/BeTe type-II superlattices

We first present the dependence of intersubband transition (ISB-T) on the electronic doping density in (CdS/ZnSe)/BeTe superlattices (SLs). The in situ RHEED and X-ray diffraction measurements reveal these SLs with perfect structure. An ISB-T energy as high as 0.787 eV is observed in this structure. The intensity of ISB absorption increases with increasing ZnCl₂ flux until reaches a maximum and then decreases with further more ZnCl₂ flux supplying. The ISB-T energy slightly red shifts from 0.787 to 0.775 eV with ZnCl₂ flux increasing and then blue shifts to 0.785 eV when the intensity of ISB decreases with more chlorine doping. Finially, The anneal effects on the properties in (CdS/ZnSe)/BeTe as well as CdS/ZnSe structures are studied. The explanations to result in the change in (CdS/ZnSe)/BeTe and CdS/ZnSe structures are given. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)