Empirical rule of intrinsic absorption spectroscopy in Hg1−xCdxTe

An empirical formula for the calculation of the intrinsic optical absorption coefficient at the Kane region is derived as α=αg exp[β(E−Eg)]1/2 from the measured absorption spectra in the whole intrinsic absorption region for Hg1−xCdxTe with different composition x from 0.170 to 0.443. The parameter β depends on composition x and temperature T, β=24−18x at 300 K and β=5.4+11x at 77 K. The calculated results from this simple empirical formula also agree well with those derived from the Kane model.