Optical Properties of Vacuum-Evaporated Selenium and Tellurium

Abstract

The optical properties of evaporated films of Se and Te at room temperature have been determined in the energy range from 5–25 eV. In addition the real part of the refractive index has been determined for Te up to 38 eV. The films used were of high quality, prepared and measured in vacuum (−5 Torr), and reflectances were significantly higher than reported in previous literature. The optical properties of Se and Te are similar; both show structure in the imaginary part ε_Z of the dielectric constant ε between 7 and 9 eV identified with interband transitions. The calculated energy‐loss function ‐ Im(ε+1)⁻¹ shows a maximum at 14.5 eV in Se and at 11.3 eV in Te. The calculated energy‐loss function ‐ Im(ε)⁻¹ shows peaks at 5.25 and between 18.5 and 19.0 eV for Se and at 5.6 and 17.2 eV for Te. These optical data agree with published characteristic electron‐energy‐loss measurements and allow identification of the modes of energy loss involved.