Characterization of epitaxial Hg/sub 1-x/Cd/sub x/Te layers using the far infrared optical method

Far infrared (FIR) reflectivity versus the wavelength, at room temperature, was measured for Hg/sub 0.8/Cd/sub 0.2/Te epitaxial layers grown on three CdTe semiinsulating substrata. The epitaxial single crystals were grown using vapour deposition techniques. The epitaxial film, grown on the best substratum, was successively etched with 0.2 % Br/sub 2/ methanol etchant. Far IR reflectivity diagrams for seven various thicknesses of Hg/sub 0.8/Cd/sub 0.2/Te film were measured. The experimental diagrams were numerically analyzed and it was shown that the values of optical transverse modes for both HgTe like and CdTe like modes were practically constant. This means that the composition of the epitaxial layer was unchangeable near the surface down to 0.9 /spl mu/m from the surface.