OPTICAL GAIN IN THE NITRIDES - ARE THERE DIFFERENCES TO OTHER III-V SEMICONDUCTORS

We have studied the optical gain spectra in GaInN/GaN and GaN/AlGaN do uble heterostructures and quantum wells at room temperature employing the stripe-excitation method. We compare the results with data for oth er III-V semiconductors. The optical gain is strongly anisotropic, wit h almost no gain for the TM mode. For quantum wells, the material gain increases with decreasing well width as expected. Whereas for GaInN/G aN structures only a single gain peak is observed, consistent with a f ree-carrier gain model, measurements on GaN/AlGaN structures reveal tw o peaks, which are assigned to localized exciton and exciton-LO-phonon gain. (C) 1997 Elsevier Science S.A.