Electric field dependence of the excitonic properties in graded double quantum wells

Abstract

A quasi-bound state approximation is used to obtain the electric field dependence of the eigenvalues, eigenfunctions, electron-hole overlap integrals and excitonic binding energies for coupled, graded double quantum wells (GDQWs). In GDQWs the intra- and interband transitions have a much stronger electric field dependence than those in the square quantum well structures. Also, unlike the single or double square wells the operation wavelength of GDQW devices can be tuned by changing not only the magnitude but also the polarity of the applied voltage. Thus GDQWs have potential for applications in optoelectronic devices such as tunable electro-absorption modulators and infrared photodetectors.