QUANTUM-WELL ALXGA1-XAS-GAAS HETEROSTRUCTURE LASERS GROWN BY METALORGANIC CHEMICAL VAPOR-DEPOSITION

Data are presented on photopumped single- and multiple-quantum-well AlxGal-xAs-GaAs heterostructures grown by metalorganic chemical vapor deposition (MO-CVD) showing that continuous room-temperature (CW 300 K) laser operation of such structures is possible in the range 0–150 meV above the GaAs active region band edge (ΔE≡fiw - Eg = 0–150 meV). Optically pumped multiple-quantum-well heterostructure lasers of short cavity length (1: < 20 μm), and thus high edge-to-edge cavity end losses, are shown to operate at photo-excitation threshold levels as low as 900 W/cm2(Jth∼ 375 A/cm2). As the quantum-well dimension is reduced to Lz< 100 Å single-active-layer heterostructures shift their laser operation to higher confined-particle states, or fail to operate altogether, whereas multiple-active-layer heterostructures continue to operate as lasers on the lowest confined-particle states n = 1 e →hh and n’ = 1’ e →lh transitions). For a multiple-Quantum-well heterostructure of small enough GaAs active region size, Lz < 80 A, recombination radiation at the energy gap is cut off, and as expected, laser operation on the lowest confined-particle states (1 - 1’) is shifted to high energy (Ilw - Eg > 50 meV). Copyright © 1979 by The Institute of Electrical and Electronics Engineers, Inc.