NONRADIATIVE CURRENT IN INGAAS ALGAAS LASER-DIODES AS A MEASURE OF FACET STABILITY/

We present a novel, non-destructive optoelectronic technique to study passivation and degradation mechanisms at diode laser facets. We extra ct the non-radiative current components, I-nr, from the electrolumines cence power-voltage-current characteristics. In InGaAs/AlGaAs (lambda = 0.98 mu m) laser diodes these currents have been identified as being primarily related to surface recombination, which increases during fa cet degradation. and can he decreased by a sulphur treatment. An analy sis of the logarithmic change of I-nr with facet degradation or passiv ation shows a typical maximum or minimum respectively, which can be in terpreted as a change in charge and density of a certain surface state . This technique permits relaxation processes to be analyzed quantitat ively. (C) 1998 Elsevier Science Ltd. All rights reserved.