Optical gain in ZnCdSe-ZnSe quantum well structures

Abstract

ZnSe-ZnCdSe quantum well structures are the most likely candidate for the fabrication of commercial blue-green semiconductor lasers. Devices incorporating these wells have achieved room temperature cw lasing at 510nm with operating lifetimes of up to 100 hours. In wide band gap semiconductors the increased binding energy and higher effective masses cause an increase in the Coulomb enhancement of the recombination rate and a decrease in the scattering lifetime of the carriers. The dependence of the optical matrix element on the inverse of the energy gap also means that the available gain in wide band gap materials is significantly lower than in narrow band gap semiconductors. Therefore the prediction of a wide band gap semiconductor light emitting device’s performance is not simply an extrapolation from that of a device incorporating narrow band gap III-V materials.