FREE-CARRIER ABSORPTION BY PHOTON-IONIZED-IMPURITY-PLASMON PROCESSES IN POLAR SEMICONDUCTORS

Absorption of electromagnetic radiation by free carriers is conditioned by their interaction with lattice imperfections. Both individual carrier transitions and generation of collective plasma oscillations (plasmons) may contribute to this absorption. Photon-ionized-impurity (defect)-plasmon processes at radiation frequency close to plasma frequency are discussed in detail and shown to be important in polar semiconductors with high static (lattice) dielectric constant and high carrier concentration. The theoretical results are compared with the experimental data on plasmon generation in n-PbSe in infrared. © 1978 The American Physical Society.