THE INFLUENCE OF TENSILE STRAIN ON DIFFERENTIAL GAIN AND AUGER RECOMBINATION IN 1.5-MU-M MULTIPLE-QUANTUM-WELL LASERS

A systematic study has been undertaken including growth, characterizat ion, and modeling of tensile-strained multiple-quantum-well (MQW) lase rs with emission wavelengths in the neighborhood of 1.5 mu m. The lase r threshold increases between 0% and -0.5% mismatch, switching from TE to TM polarized emission at -0.5%, then decreases to -1.3% mismatch, with TM polarized emission. The threshold current density has a much w eaker dependence on inverse cavity length in the highly tensile-strain ed lasers than has previously been observed for lattice-matched and co mpressive lasers emitting in the same wavelength range. We present the oretical calculations which show that the observed differences are wel l explained, both qualitatively and quantitatively, by the calculated variation with strain of the optical confinement factor Gamma and the differential gain at transparency, dg/dn (n(tr)). More detailed compar ison with experiment suggests that Auger recombination provides the do minant contribution to the threshold current density. Estimated Auger coefficients C are in good agreement with those previously obtained us ing other techniques.