LAUSR

Abstract Using a combination of reflectivity and ellipsometry, we determined the far-infrared dielectric functions of molecular beam epitaxy-grown Hg1−xCdxSe thin films between 85 cm−1 and 8, 000 cm−1. Spectroscopic ellipsometry, performed between 400 cm−1 and 8000 cm−1, recovered the dielectric function and the thickness of each film. Ellipsometry results were then used to model the reflectivity data allowing us to obtain absolute reflectance values and map the dielectric function from reflectivity between 85 cm−1 and 8, 000 cm−1, and to obtain the absorption due to free electrons, phonons, and band electrons. Specifically, our models find two transverse optical modes for Hg1−xCdxSe, where the HgSe-like mode blue-shifts and the CdTe-like mode red-shifts with increasing Cd concentration.