Composition and temperature dependence of the refractive index in Hg1-xCdxTe over the visible light region

We measured refractive index of n type Hg1-xCdxTe with the null ellipsometric spectrum method over the visible light region, and the dispersion spectra with compositions x ranging from 0.2 to 0.46 have been obtained at different temperature. The reflectivity has been calculated in the wavelength region above the absorption edge at temperatures from 77K to 300K. A peak over the visible light region appears just at the wavelength corresponding to the band-gap energy E-1(x,T) of Hg1-xCdxTe. E-1(x,T) can be described by an empirical formula.