Analysis of leakage currents in MOCVD grown GaInAsSb based photodetectors operating at 2 µm

This paper reports the fabrication and characterization of GaInAsSb photodetectors operating at 2 μm. At room temperature, the performance of these photodiodes under reverse bias conditions is limited by the surface leakage. A model has been developed to separate the bulk (diffusion and generation-recombination (g-r)) and the surface leakage contributions toward the total leakage current. By fitting this model to the experimental data, values of material parameters such as minority carrier diffusion length and lifetime have been estimated. The highest R₀A of 55 Ω-cm² has been obtained with a responsivity of 0.44 A/W at 2 μm.