Defect structures in rapidly degraded InGaAsP/InGaP double-heterostructure lasers

Abstract

Rapidly degraded InGaAsP/InGaP double-heterostructure lasers grown on (001)-oriented GaAs substrates by liquid phase epitaxy have been investigated by photoluminescence topography and transmission electron microscopy. 〈100〉-dark-line defects and 〈110〉-dark-line defects are observed in the degraded region. The 〈100〉-dark-line defects correspond to interstitial type dislocation dipoles caused by recombination enhanced dislocation climb. Their origins are threading dislocations, V-shaped dislocations, and dislocation networks. The 〈110〉-dark-line defects correspond to faulted dipoles extended from small faulted loops in the active layer, edge dipoles extended from threading dislocations, and glide dislocations. The velocities of the 〈100〉-dark-line defects are estimated by the operating time and the length of the dark lines, and are quite similar to those in rapidly degraded GaAlAs double-heterostructure lasers.