Free-Carrier Absorption in Quantum Well Structures for Alloy-Disorder Scattering

Abstract

A theory of free-carrier absorption is given for quantum well structures fabricated from III-V semiconducting materials when the carriers are scattered by alloy-disorder. Results show that the absorption coefficient decreases with increasing photon frequency and increases with increasing temperature. It is also shown that the absorption coefficient increases with decreasing layer thickness. In addition, it was found that in quantum well structures the electron-alloy-disorder interaction gives greater contribution to the absorption than the electron-acoustic and piezoelectric phonon interaction.