Modeling of intersubband and free-carrier absorption coefficientsin heavily doped conduction-band quantum-well structures

摘要

Theoretical modelings of the transition energy for intersubbandnabsorptions, and the intersubband and free-carrier absorptionncoefficients in heavily doped conduction-band anisotropic semiconductornquantum-well (QW) structures are presented. The transition matrixnelements for photon absorption and emission, which are not identical duento the different many-body effects involved in the photon absorption andnemission processes, are rigorously derived. We also show that thenlinewidth broadening effect caused by various scattering processes givesna considerable increase in resonance energy, which explains thenrelatively large parallel-mode transition energy which cannot beninferred from previous modeling studies. In addition, theoreticalnmodeling of free-carrier absorption in anisotropic semiconductor QWnstructures is presented for the first time. The calculated results arencompared with the experimental values for Δ-doped Si QW's