Reduction of threshold current density in GaAs–Al<i>x</i> Ga1−<i>x</i> As heterostructure lasers by separate optical and carrier confinement

Abstract

Heterostructure lasers in which the GaAs active layer is bounded on each side by successive layers of AlxGa1−xAs to confine the carriers and AlyGa1−yAs (y&amp;gt;x) to confine the light have been fabricated and studied. Room-temperature threshold current densities as low as 690 ± 40 A/cm2 with differential quantum efficiencies of 32% have been obtained for 1-mm cavity lengths.