Impact of neutron irradiation on optical performance of InGaAsP laser diodes

Results are presented of an extended study on the degradation and recovery behavior of optical and electrical performance and on induced lattice defec ts of 1.3 mu m InGaAsP double channel planar buried heterostructure laser d iodes with an In0.76Ga0.24As0.55P0.45 multi-quantum well active region, sub jected to a 1 MeV fast neutron and I MeV electron irradiation. The degradat ion of the device performance increases with increasing fluence. Two hole c apture traps with near midgap energy level in the In0.76Ga0.24As0.55P1.45 m ulti-quantum well active region are observed after a 1 x 10(16) n/cm(2) irr adiation. These deep levels are thought to be associated with a Ga vacancy. The decrease of optical power is related to the induced lattice defects, l eading to a reduction of the non-radiative recombination lifetime and of th e carrier mobility due to scattering. The difference in radiation damage be tween 1 MeV fast neutrons and 1 MeV electrons is discussed taking into acco unt the nonionizing energy loss (NIEL). The radiation source dependence of performance degradation is attributed to the difference of mass and the pro bability of nuclear collision for the formation of lattice defects. The dec reased optical power recovers by thermal annealing, and the recovery increa ses with increasing annealing temperature. The optical power recovers by 45 % for 1 MeV neutron irradiation with a fluence of 1 x 10(15) n/cm(2) after a 300 degrees C annealing. (C) 2000 Elsevier Science S.A. All rights reserv ed.