Visible and Ultraviolet Reflectivity of Hg0.8Cd0.2Te

The fundamental reflectivity spectra of Hg0.8Cd0.2Te have been investigated. The feature of the spectra is the presence of E1 and E2 peaks within the fundamental absorption region. A three-dimensional saddle point is used to fit the E1 and E1 + Δ1 critical point and some simulated calculation is done for E2 at X point. The measured and calculated reflectivities are compared and prominent features of the reflectivity spectra are identified with critical point transition at the Λ and X points in the Brillouin zone.