Dark current reduction in AlxGa1−xAs-GaAs heterojunction diodes

The addition of a thin, high band-gap P(N)-type AlxGa1−xAs layer into a conventional AlyGa1−yAs-GaAs N-p (P-n) heterojunction is found to significantly reduce the 2kT recombination current, thereby permitting the bulk diffusion current to dominate at current densities as low as ∼10−5 A/cm2. Experiment indicates that the 2kT current is due to surface-recombination processes and originates in a very narrow region near the p-n junction, presumably due to the small minority-carrier surface-diffusion length.