Intersubband transitions in coupled triple-graded quantum wells under an electric field

The intersubband transitions were calculated in three different shaped triple-graded quantum wells. The investigation involved changing the depth of the central well potential under an electric field applied parallel to the growth direction. By changing the depth of the central well potential, one can tune the resonance photon energy. This tunability gives a possibility for the realization of near-infrared electroabsorption modulators and detectors. In addition, the absorption coefficient as a function of the incident photon energy was obtained for the 1-2 transition in a triple square quantum well structure having the same physical parameters as the triple-graded quantum well structure. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.