Optical properties of amorphous and polycrystalline BeO thin films from electron energy loss measurements

Abstract

Abstract Energy loss measurements on amorphous and polycrystalline BeO thin films are performed applying 25 keV electrons. From the energy‐dependent loss function Im (−1/ε) the dielectric function and its first energy derivative, the reflectance, η eff , ε 2 E 2 up to 44 eV are computed using the Kramers‐Kronig‐analysis and well‐known formulae. The results obtained on polycrystalline BeO are discussed with respect to band structure information. The corresponding spectra of amorphous BeO are compared with those of the polycrystalline material.