Degraded InGaAsP/InP double heterostructure laser observation with electron probe microanalyzer

Abstract
Dark spots associated with degradation in InGaAsP/InP double heterostructure lasers were examined by electron probe microanalyzer, cathodoluminescence micrograph, and sequential selective etching procedures. It has been clarified that these dark spots penetrate from the p-cladding layer to the n-cladding layer and have no direct relation with InP substrate defects. Segregation of As and Ga in an active layer geometrically correlates with these dark spots. Dark spot generation and segregation were seen to develop with degradation induced in the laser operation.