The facets of GaAs-AlGaAs ridge waveguide (RW) laser diodes were passi
vated using (NH4)(2)S-x. The effectiveness of this procedure was check
ed by electroluminescence power-voltage-current (P-V-I) measurements t
hat provide information on the changes in the density of surface state
s, Using this nondestructive method, the degradation of the passivatio
n under ambient atmosphere has been studied. Capping with silicon nitr
ide is found to stabilize the sulfur passivation and avoid degradation
.