Optical properties of ZnGeN2 epitaxial layer

Reflectance spectra of a ZnGeN2 epitaxial layer have been measured by using synchrotron radiation in the photon energy range of 2 to 120 eV. The peak of the reflectance spectra shifts to low energy by changing the direction of the electric vector. The optical constants including the complex index of refraction and the complex dielectric constant were determined on the basis of the Kramers-Kronig analysis for the first time. The refractive index n calculated from the reflectance spectra agrees with that measured by ellipsometry. For the imaginary part of the dielectric constant epsilon(2), comparing the peak position of experimental and theoretical spectra, there is agreement between both sets of data. The anisotropy of the optical properties was investigated. (C) 2003 WILEYNCH Vertag GmbH & Co. KGaA, Weinheim.