Visible and near-infrared responsivity of femtosecond-laser microstructured silicon photodiodes

Abstract:

We investigated the current-voltage characteristics and responsivity of photodiodes fabricated with silicon that was microstructured using femtosecond-laser pulses in a sulfur-containing atmosphere. The photodiodes we fabricated have a broad spectral response ranging from the visible to the near-infrared (4001600 nm). The responsivity depends on substrate doping, microstructuring fluence, and annealing temperature. We obtained room- temperature responsivities as high as 100 A/W at 1064 nm, two orders of magnitude higher than standard silicon photodiodes. For wavelengths below the band gap, we obtained responsivities as high as 50 mA/W at 1330 nm and 35 mA/W at 1550 nm.