Electroluminescence spectra of 80 Aring; GaxIn1minus;xP/(Al0.6Ga0.4)0.5In0.5P quantum wells (QWs), withx=0.3, 0.4, 0.5, and 0.6, are examined. The polarization is anisotropic, and the lighthyphen;hole (lh) and heavyhyphen;hole (hh) transitions are resolved at current densities between 1 A/cm2and threshold. In the compressively strained (x=0.3, 0.4) QWs, the hh is ground state and transverse electrichyphen;mode emission dominates. The lh and hh band edges are reversed for the tensilehyphen;strained QW, however, and the emission is predominantly transverse magnetic. Near threshold, the bandfilling effect is most pronounced in the compressively strained QWs, suggesting a reduced inhyphen;plane hh effective mass. For the most highly compressed QW (x=0.3, lgr;=707 nm), the threshold current density is 190 A/cm2.
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