No abstract

No abstract

The negatively charged exciton (X-) is observed to strongly couple with the microcavity- (MC-)confined photons in a GaAs quantum well containing a two-dimensional electron gas with 0

The photoluminescence (PL) spectrum of modulation-doped GaAs/AlGaAs quantum wells (MDQW) and heterojunctions (HJ) is studied under a magnetic field (B ) applied parallel to the two-dimensional electron gas (2DEG) layer. The effect of B strongly depends on the electron-hole separation (d eh ), and we revealed remarkable B -induced modifications of the PL spectra in both types of heterostructures. A model considering the direct optical transitions between the conduction and valence subband that are shifted in k-space under B , accounts qualitatively for the observed spectral modifications. In the HJs, the PL intensity of the bulk excitons is strongly reduced relatively to that of the 2DEG with increasing B . This means that the distance between the photoholes and the 2DEG decreases with increased B , and that free holes are responsible for the hole-2DEG PL.

No abstract