Determination of cut-off wavelength and composition distribution in Hg_1-xCd_xTe

The determination of cut-off wavelength, λ_co, and composition distribution for Hg_1-xCd_xTe has been discussed in this paper. A shift of the cut-off wavelength was found from the photo-response calculation for the HgCdTe devices with the same energy gap E_g but different thickness d. An expression of λ_co(x,T,d) has been derived from the half-maximum photo-response curve calculation. The composition uniformity has been determined from the room-temperature transmission fitting procedure. The composition real space distribution is suggested to be determined by the combination of absorption edge phenomenon and thermal imaging technique.