ALLÈGRE , Jacques

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 have grown GaN films and GaN–AlGaN quantum wells (QWs) on homoepitaxial substrates, by molecular beam epitaxy using ammonia. Both the GaN film and the QW are found to have superior excitonic recombination properties which are extremely promising for the development of indium free ultra-violet lasers based on nitrides.

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...