Stimulated emission in strained-layer quantum-well heterostructures

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Abstract
Stimulated emission data are presented on a large variety of strained‐layer quantum‐well heterostructures (QWH’s) and superlattices (SL’s) grown by metalorganic chemical vapor deposition (MOCVD). These structures consist of barrier‐well combinations of thickness LB,Lz ≲150 Å made from GaAs‐InGaAs, GaAsP‐GaAs, and GaAsP‐InGaAs. Also employed are higher band‐gap confining layers of InxAlyGa1‐x‐yAs, AlyGa1−yAs1−xPx, and AlxGa1−xAs. All of the heterostructures are grown on a GaAs substrate with and, in some cases, without a graded layer. The strain range between 0.2 to 12.5×10−3 is examined. Photopumped, these heterostructures operate as continuous (cw) 300 K lasers, with thresholds of 1.6–7.5×103 W/cm2, for periods of time between 0.5 to >35 min. Under high‐level excitation, the equivalent of Jeq∼103 A/cm2, laser operation fails or is quenched by networks of dislocations (with 〈110〉 Burger’s vectors) that are generated within the strained‐layer region of the QWH’s or SL’s. These dislocation networks, which are revealed via transmission electron microscopy (TEM), occur at a more rapid rate in higher threshold samples and ones with higher built‐in strain. The TEM data show, however, that no heterointerface defects <named-content xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"...