RAMAN-SCATTERING OF SE-DOPED GALLIUM NITRIDE FILMS

Abstract

Raman spectra of Se-doped gallium nitride films have been measured for the first time with good resolution and a wide range of excitation wavelengths. The signals from both buffer layer and epilayer are identified unambiguously. We have observed not only the resonant scattering related to the transition below the band gap but also the phonon-plasmon coupling due to the doping effect. The carrier concentration obtained from lineshape fitting is consistent with that from Hall measurements. By comparing the Raman shifts with those of other nitrides and gallium compounds, we found that most of them are almost linearly proportional to the square root of reciprocal masses. The bonding strengths are thus inferred from the slopes.