Abstract
We report on optoelectronic properties of devices based on Si/Si
1−
x
Ge
x
systems. To limit the inherent problems of the type II character and the indirect nature of the bandgap, we propose Si/Si
1−
x
Ge
x
strained QW
s embedded in relaxed Si
1−
y
Ge
y
barriers. The conduction and the valence band present a W-, Usami- or M-like potential profile with a quasi-type I heterostructures. Based on Schrödinger equation, a theoretical analysis is made to calculate electric field dependent interband transitions in the three above-mentioned structures. The thickness and compositions (
x
>
y) of these heterostructures are computed in order to get: (i) the optimum quantum confinement of electrons and heavy-holes levels; (ii) the optimum out of plane oscillator strength and wave functions overlap; (iii) to satisfy a fundamental emission at a key 1.55
μm wavelength below the absorption gap of the three designed structures. The effect of the applied electric field on quantum levels and oscillator strength is discussed.