Optical absorption above the energy band gap in Hg_1-xCd_xTe

Based on the intrinsic absorption spectra of Hg_1-xCd_xTe performed on thin films of Hg_1-xCd_xTe bulk material with x ranging from 0.170 to 0.443 and at temperatures from 4.2 to 300 K, the expressions for the intrinsic optical absorption coefficient in the Kane region are reviewed. The results show that the energy dependence of the absorption coefficient above the absorption edge obeys an exponential law rather than a square-root law. Furthermore, it seems that the absorption behavior of the epitaxial film in the Kane region also follows the exponential absorption law.