CW and time-resolved optical spectroscopy of GaN epilayers and GaN-AlGaN quantum wells grown on A-plane sapphire

Optical anisotropy in the growth plane has been observed by reflectance and photoluminescence (PL) spectroscopy on nitride epilayers grown on A-plane sapphire. This anisotropy results from the strongly anisotropic thermal str ain which is such that the wurtzite symmetry goes from Cg, to C-2v Time-res olved PL reveals less marked anisotropy for PL decay times, due to the cont ributions of both radiative and non-radiative recombination channels. Never theless, by using a multilevel modelling of the time-dependent PL accountin g for the optical anisotropy, we are able to separate the two types of reco mbinations. Last, we present cw and time-resolved PL results on GaN-AlGaN s ingle quantum wells grown on A-face sapphire.