The influence of structural properties on the refractive index of AlN films grown on Si(111) substrates by molecular-beam epitaxy using ammonia was reported. The structural properties were assessed by using reflection high-energy electron diffraction, atomic force microscopy, transmission electron microscopy and X-ray diffraction methods. The evidence revealed an influence of strain and dislocation density upon the refractive index.

Correlation between Threading Dislocation Density and the Refractive Index of AlN Grown by Molecular-Beam Epitaxy on Si(111). F.Natali, F.Semond, J.Massies, D.Byrne, S.Laügt, O.Tottereau, P.Vennéguès, E.Dogheche, E.Dumont: Applied Physics Letters, 2003, 82[9], 1386-8