Electrical crosstalk suppression for mesa-based in-device passivated InGaAs photodetectors

Inclusion of an in-device passivation layer in mesa-based lattice-matched InGaAs photodetectors provides a lower dark current than the conventional mesa type structures. However, due to the high electric field in the passivation layer between the pixels, improved dark current characteristics come with increased electrical crosstalk. Manipulating the electrical field distribution with an additional thin epilayer promises to reduce this inter-pixel carrier collection without disturbing the primary aim of the passivation layer, which is to reduce the dark current through the depleted condition. An experimental-like scanning demonstration with a five-pixel mini array numerically shows a significant decrease in electrical crosstalk together with an increase in photo-response.

Automated summary

This study investigates the inclusion of an in-device passivation layer in mesa-based lattice-matched InGaAs photodetectors. The passivation layer reduces the dark current but increases electrical crosstalk. By adding a thin epilayer, the electrical field distribution can be manipulated to reduce inter-pixel carrier collection and improve the photo-response.