γ-Irradiation Damage Mechanism of InGaAs/InP p–i–n Focal Plane Array Investigated by Spatially Resolved and Temperature-Dependent Photoluminescence

InGaAs infrared photodetectors subjected to irradiation environments undergo microstructural modifications and concomitant degradation, yet the underlying microscopic mechanism has not been fully studied. Herein, the influence of γ irradiation (total dose of 20 krad(Si)) on an In_0.53Ga_0.47 As/InP p–i–n focal plane array is studied by spatially resolved and temperature-dependent (3–290 K) photoluminescence (PL) measurements. By comparative PL studies of pre-irradiation and post-irradiation, the spatially resolved PL results of irradiation indicate that the in-plane uniformity of all PL features presents bigger fluctuations, meanwhile, the results of temperature-dependence PL demonstrate that the PL integral intensity related to impurities and interface-bound states is significantly weakened after irradiation. This can be attributed to the enhanced migration and reaction of defects caused by γ irradiation. Some mobile defects tend to migrate to lower energy regions, such as interfaces, and form defect complexes. In addition, some impurities combine with mobile defects and form inactive impurity–defect complexes. The findings reveal the effects of low-dose γ irradiation on InGaAs devices and may provide useful information for enhancing radiation resistance.