Effect of nonparabolicity on free-carrier absorption in n-type InSb films for polar optical phonon scattering

The free-carrier absorption in n-type InSb films has been studied for quantum well structures fabricated from III-V semiconducting materials where the polar optical phonon scattering is predominant. We consider here two special cases: the electromagnetic radiation is polarized parallel to the layer plane and perpendicular to the layer plane separately. The energy band of electrons in semiconductors is assumed to be nonparabolic. Results show that when the electromagnetic radiation is polarized parallel to the layer plane, the free-carrier absorption coefficient is independent of temperature in a small quantum well region such as d < 30 Angstrom, but the absorption coefficient oscillates with the quantum well and depends upon the temperature in the region of larger quantum wells. When the electromagnetic radiation is polarized perpendicular to the layer plane, the dependence of the free-carrier absorption coefficient on the quantum well and temperature becomes quite complicated. (C) 1999 Elsevier Science B.V. All rights reserved.