Study of the dielectric function of hexagonal InN: Impact of indium clusters and of native oxide

The complex dielectric function of hexagonal InN has been determined in the 0.72-6.50 eV photon energy range using spectroscopic ellipsometry. The InN films have been synthesized using molecular beam epitaxy on Si-face 6H-SiC0001 substrates. The fundamental band gap E0 and higher energy interband critical points have been identified at room temperature. The impact of indium clusters and of the InN native oxide on the dielectric function is discussed