Résumé:

We calculate the spectroscopy of is excitons in GaN epilayers grown with biaxial stress on [10(1)over-bar0]-oriented M plane. In contrast to the growth on conventional C-plane substrates, for which we predicted five radiative excitons, we now demonstrate the existence of nine radiative transitions. A, B, and C excitons are now radiative for any polarization case, due to the crossed configuration of the wurtzite crystal field and the built-in strain one. In particular, the A exciton is significantly coupled to the electromagnetic field in pi polarization (E parallel to c). Strong in-plane anisotropy of the optical response is predicted and computed.