Coulomb enhancement of the optical gain in quantum well structures

Coulomb enhancement has been regarded as the main cause for the increase in optical gain in quantum well structures, and it has usually been dealt with using the Padé approximation. In this Letter, we have studied the “Coulomb enhancement” factor based on the semiconductor Bloch equation for the ind...

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Bibliographic Details
Published in:Physics letters. A 2004-08, Vol.329 (1), p.116-129
Main Author: Ren, G.B.
Format: Article
Language:English
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Summary:Coulomb enhancement has been regarded as the main cause for the increase in optical gain in quantum well structures, and it has usually been dealt with using the Padé approximation. In this Letter, we have studied the “Coulomb enhancement” factor based on the semiconductor Bloch equation for the induced dipole beyond the Padé approximation. Considering the angular dependence of the dipole matrix element, we investigate the effect of “Coulomb enhancement” on the optical gain in wurtzite and cubic quantum well structures. We have calculated optical gain spectra at various carrier densities in a 50 Å GaN/Al 0.2Ga 0.8N quantum well including the Coulomb enhancement factor. Our study indicates that the “Coulomb enhancement” factor may change the refractive index of the material and affect the dynamic properties in a quantum well laser, however, the enhancement to the optical gain is small and may be overestimated in literature.
ISSN:0375-9601
1873-2429
DOI:10.1016/j.physleta.2004.06.067