Band structure engineering in strain-free GaAs mesoscopic systems.

We investigate the optical properties of strain-free mesoscopic GaAs/Al Ga As structures (MGS) coupled to thin GaAs/Al Ga As quantum wells (QWs) with varying Al content (x). We demonstrate that quenching the QW emission by controlling the band crossover between AlGaAs (X-point) and GaAs (Γ-point) gives rise to long carrier lifetimes and enhanced optical emission from the MGS. For x = 0.