MATHIEU , Henry

Very strong coefficients for spontaneous and piezoelectric polarizations have recently been predicted for III-V nitride semiconductors with natural wurtzite symmetry. Such polarizations influence significantly the mechanisms of radiative emissions in quantum-confinement heterostructures based on these materials. The photoluminescence decay time...

The 2-K recombination dynamics of coupled GaN-AlGaN multiple quantum wells reveals a composite nature in terms of the joint contributions of short-lived direct excitons and long-lived oblique ones. The possibility to observe these oblique excitons, which produce a unusual blueshift of the photoluminescence at long decay times is found to be in...

We compare several InGaN-based low-dimensional systems, by time-resolved photoluminescence (PL), versus temperature (8

Time-resolvedphotoluminescence (PL), at T=8 K, is used to study a graded-width InGaN/GaN quantum well. Across the sample, the well width continuously varies from ∼5.5 to 2.0 nm corresponding to PL peak energies varying between 2.0 and 2.9 eV and to PL decay rates covering four orders of magnitude. The plot of decay times versus PL energies is...

We present low-temperature-reflectance experiments, performed on GaAs-Ga1−xAlxAs asymmetrical double quantum wells, under in-plane uniaxial stress. The results, when compared to what is obtained from single quantum wells, exhibit some peculiar behaviors, which are typical effects of the asymmetry of the structures. A careful examination of...

Reflectance spectra are studied for both symmetric and asymmetric double-quantum-well structures separated by intermediate barriers with various thicknesses. It is shown that the interwell couplings versus the tunneling of the carriers across the barrier has a significant influence on the optical transition properties. Quantitative analyses are...