Coulomb interaction of electron gas in MQWs Si/Si1 − xGex/Si

We present a theoretical analysis of the conduction and valence-band diagrams of SiGe/Si Multiple Quantum Wells (MQWs), having a specific “W” geometry, and designed for emission or photodetection around the 1.55 μm wavelength. Peculiar features have been extrapolated by solving self-consistent Schrödinger and Poisson equations, taking into account the electrostatic attraction induced by carrier injection. As a result, Coulomb interaction strongly modifies the band profiles and increases the electron probability density at the quantum well interfaces; the injected carrier concentration enhances electron–hole wave functions overlap and the in-plane oscillator strength. These MQWs structures, strain-compensated on relaxed Si0.75Ge0.25 pseudo-substrates, are potentially interesting for telecom applications.