Surface plasmons at MOCVD-grown GaN(000(1)over-bar)

We report on the first observation of surface plasmons at a GaN surface by high-resolution electron energy loss (HREEL) spectroscopy. Dipole scatterin g theory using self-consistent electron density profiles is employed to cal culate the surface energy loss function and hence the expected energy loss spectra. The characteristic features of both the surface plasmons and the F uchs-Kliewer (FK) surface optical phonons are well reproduced in the framew ork of this model. Fitting measured HREEL spectra allows us to give estimat es of important semiconductor parameters such as electron density, electron mobility and band bending. Moreover, it is found that the plasmon damping strongly depends on primary beam energy. Similarly, the FK phonon damping a nd frequency are also affected by the variation of primary beam energy.