Nature of 〈110〉 dark-line defects in degraded (GaAl)As-GaAs double-heterostructure lasers

The 〈100〉 dark-line defects (DLD’s) in the degraded (GaAl)As-GaAs double-heterostructure lasers are studied by transmission electron microscopy. Two types of 〈110〉 DLD’s are observed; one is associated with 〈110〉 straight dislocations and the other with dislocation networks developing from the mirror surface. The former type of the 〈110〉 DLD’s is found to be formed by dislocation glide motion. The development of the 〈100〉 dislocation dipole from the 〈110〉 dislocation is also observed, indicating that the 〈110〉 dislocation is a source of the 〈100〉 dislocation dipole.