T. OsotchanV. W.L. ChinT. L. TansleyMacquarie UniversityMahidol UniversityUniversity of New South Wales (UNSW) Australia2018-07-042018-07-041996-11-01Journal of Applied Physics. Vol.80, No.9 (1996), 5342-5347002189792-s2.0-0003719304https://repository.li.mahidol.ac.th/handle/20.500.14594/17838Optical transitions for the (001) Al0.3Ga0.7As/AlAs/GaAs double-barrier superlattices are evaluated by a semiempirical, tight-binding calculation. The oscillator strength between the hole and electron states confined in either Γ- or X-like well are investigated as a function of AlAs slab thickness. Intersub-band transition within the conduction band, including Γ- and X-like superlattice (SL) states, is described for a quantum well infrared photodetector (QWIP). We found that for a specific design structure, it is possible to achieve the dual wavelength QWIP with comparable oscillator strength for the 3-5 μm and 8-14 μm atmospheric windows. In addition, by varying the AlAs barrier thickness, the characteristics of bound-to-continuous and bound-to-quasibound QWIPs are related to the stationary discrete SL states. As the AlAs thickness increases, the bound-to-continuous state transition becomes weak while the bound-to-quasibound state transition becomes more significant. Optical coupling between X-like state is relatively weak and the transition between the different characteristic states is even weaker. © 1996 American Institute of Physics.Mahidol UniversityPhysics and AstronomyArticleSCOPUS10.1063/1.363473