Free-carrier absorption of Hg1−xCdxTe epitaxial films

Abstract

Free-carrier absorption (FCA) of Hg1−xCdxTe epitaxial films is analyzed by considering the composition-in-depth nonuniformity of epilayers. The results show that epilayers exhibit different FCA behavior from bulk materials. Based on the analyses, the carrier concentration, the density and size distribution of Te precipitates, as well as the inclusion in Hg1−xCdxTe epilayers are derived from fitting the measured FCA spectra.

Dispersion of refractive index in degenerate mercury cadmium telluride

“…The longwave part of both the absorption characteristics had the typical A' shape, with ~2 , which is in agreement with [13]. Ous values ~f refi-active index were slightly Sigher than 3.5, as…”

“…The effective bandgap is fmally calculated as E g g = Eg -UMBm e / -m i m p (13) where the exchange energy is obtained in eV if all the factors are given in SI units.…”

“…there is an upper electron concentration limit for its By introducing (13) instead of Eg into (4, 5) we obtain an approximate expression for the dispersion of refractive index due to interband transitions which takes into account bandgap shift caused by increased carrier concentration, i. e. valid both in nondegenerate and in degenerate case: where ~,-20.5-1.5.5~+5.7~~ [16] and E , (given above) are static and high-frequency dielectric permittivity of lmdoped material, N, is the concentration of the scattering ions, p=8.0756-2.2571~ gkm3 [16] is MCT density at 300 K, D=14.8 eV [14] is the constant of deformation potential for optical phonons, Z,,=14 eV [13] i s the constant of deformation potential, vi,=3000 m/s [13] is the longitudinal sound velocity in MCT. The values of the other parameters are taken from [ 141.…”

“…The carrier concentration was determined by the Hall measurement. We used two samples 30 p and 33 pm thick, for both of which we obtained x=0.198 using (13).…”

Feasibility of lasing in the GaAs Reststrahlen band with HgTe multiple quantum well laser diodes

“…The total loss α tot is the sum of external and internal contributions α ext , α int , where α int can be further divided into the lattice absorption coefficient α lat and the free-carrier absorption coefficient α FCA . The latter was assumed to be proportional to the carrier densities [34,44]:…”