TEM observation of catastrophically degraded Ga1-xAlxAs double‐heterostructure lasers

摘要

Defect structures of degraded GaAs/Ga1-xAlxAs double‐heterostructure (DH) lasers applied with pulsed current under high current density are studied by transmission electron microscopy. Several kinds of defects are observed corresponding to the 〈110〉 dark‐line defects which are observed in the photoluminescence patterns of the degraded DH lasers. They are arrays of dislocation tangles, nearly perfect dislocation networks, pipe‐shaped defects with strong dark contrast, and simple dislocation dipoles. The former three kinds of dislocations are assumed to be caused by the propagation of molten zone due to local heating at the mirror surface and the last defects may be caused by thermal stress.