Effect of Coulomb enhancement on optical gain in (Zn,Cd)Se/ZnSe multiple quantum wells

Abstract

The optical-gain spectra of a 40-? (Zn,Cd)Se/ZnSe multiple quantum well has been measured at various temperatures using a variable-stripe method. By comparison with a gain calculation including many-body effects, we have shown that gain in this structure arises from an electron-hole plasma (EHP) for temperatures higher than 140 K. Excellent agreement between experiment and theory allows us to demonstrate the significance of many-body effects such as carrier dephasing and Coulomb enhancement. The breakdown of the EHP model below 140 K indicates an increasing excitonic contribution.