Infrared dielectric function of wurtzite aluminum nitride

The infrared dielectric function of wurtzite AlN has been determined by fitting an analytic Lorentzian dielectric function to experimentally observed interference fringes in infrared transmission. The analytic model is scaled to agree with recent measurements of the visible refractive index, and the experiment and model extend to the submillimeter range of the infrared. A complete, experimentally verified dielectric function is found from the visible to the submillimeter spectral region for radiation with E perpendicular to c axis, and an analytic model is produced for E parallel to c axis. Refractive indices and extinction coefficients from the visible to zero frequency are presented. (C) 2005 American Institute of Physics.