Résumé
Quantum wells based on hexagonal group-III nitrides have numerous original properties. In particular, internal electric fields are present along the growth axis, reaching several MV/cm. The competition between radiative and nonradiative recombinations of electron-hole pairs in these novel nano-objects is analysed by measuring the time-resolved photoluminescencce of series of samples. The respective influences of electric fields and localisation of carriers, on the optical properties of lnGaN/GaN quantum wells, are unravelled. The scaling law observed for photoluminescence time decays and the giant coupling between LO phonons and elecrton-hole pairs are interpreted in terms of an original and efficient description of the mechanisms involved in optical recombinations.