Résumé
We performed time- and polarization-resolved pump-and-probe experiments on several differently strained GaN wurtzite epilayers.. Thanks to a selective spectral excitation of spin-polarized A-excitons at various temperatures and a fitting procedure considering the different A and B spin exciton states, we show that the Elliott-Yafet mechanism is the dominant spin-relaxation process. It origins from the high dislocation density in all of our GaN epilayers.