BIGENWALD , Pierre

Electrostatic effects which take place in group-III nitrides in their wurtzite crystallographic phase have important consequences on the optical properties of (Al,Ga)N/GaN multiple quantum wells. A low-temperature photoluminescence study shows that the behavior of the transition energy versus the barrier width is the opposite of that currently...

(Al,Ga)N/GaN quantum wells have been studied by temperature-dependent luminescence and reflectivity. The samples were grown by molecular beam epitaxy on (0001) sapphire substrates, and well widths were varied from 3 to 15 monolayers (ML's) with a 2-ML increment, thus providing a reliable data set for the study of the well width dependence of...

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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...

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