Theory of the carrier-carrier and carrier-phonon interactions under double injection into undoped quantum wells and its application to a laser problem.

Abstract

A theory is presented of the carrier-carrier and carrier-phonon interactions under double injection into undoped quantum wells of a semiconductor. The theory is developed with the use of the Green's function formalism considering that the scattering of electrons by holes and that of holes by phonons are especially important in the conduction band and in the valence band, respectively. It is assumed that heavy holes can be treated as fixed scatterers to electrons and the validity of the assumption is examined. For both electrons and holes the exchange interaction is taken into account using the plasma-pole approximation especially for the Coulomb-hole term. The theory is applied to the calculation of the laser gain. It is shown that the theory well explains an experimental result on a laser gain spectrum. The loss of the k selection by which experimental gain spectra have been explained earlier is concluded to result mainly from the hole-phonon interaction rather than from the carrier-carrier interaction. However, the spectral range of the gain is shown to be strongly dependent on the carrier-carrier interaction.