Reflectivity of HgSe and HgTe from 4 to 12 eV at 12 and 300°K

The reflectivity of etched samples of HgSe and HgTe has been measured from 4-12 eV (3000-1050 Å) at room and He temperatures. Several peaks found in the reflectivity spectrum have been assigned to interband transitions at the $L$ and $X$ points in the Brillouin zone. Doublets, which are due to the effect of spin-orbid interaction, are resolved when the samples are cooled to He temperature. The values for $L_3$ splitting (valence band) for both HgSe and HgTe are in agreement with other measurements of these materials in the visible region where a doublet due to $L_{3V}-L_{1C}$ transitions is found. Other transitions are also discussed.