Influence of surface topography on in situ reflection electron energy loss spectroscopy plasmon spectra of AlN, GaN, and InN semiconductors

This study of III-N semiconductor surfaces demonstrates that concurrent application of in situ reflection high energy electron diffraction and glancing-angle reflection electron energy loss spectroscopy (REELS) can be used during reactive molecular beam epitaxy to provide a surface sensitive, real-time determination of the surface texture and film composition. REELS spectra of rough AlN, GaN, and InN surfaces are dominated by bulk plasmons. Nearly atomically smooth topographies are found to shift the energy of the maximum of the plasmon loss peak to lower values, presumably as a result of the additional contributions from the surface plasmons. This shift to lower energies correlates well with the fraction of the topmost surface, which lies within a few degrees from the sample surface plane.