Continuous room-temperature photopumped laser operation of modulation-doped AlxGa1−xAs/GaAs superlattices

Abstract

The low‐threshold continuous room‐temperature laser operation of a photopumped metalorganic chemical vapor deposition Al_xGa_1−x As‐GaAs superlattice is described. The superlattice, a bare superlattice without cladding or confining layers, consists of 25 140‐Å Al_xGa_1−x As (x∼0.3) coupling barriers doped to a level n_d ∼7×10¹⁷/cm³ and 25 alternating undoped 140‐Å GaAs quantum wells. Low‐temperature data (77 K) are presented indicating that the threshold for phonon‐assisted recombination occurs near the excitation level at which the excess carrier density approaches the built‐in carrier density ∼7×10¹⁷/cm³ of the superlattice.