Competition between sub-bandgap linear detection and degenerate two-photon absorption in gallium arsenide photodiodes

Benjamin Vest, Baptiste Fix, Julien Jaeck, Riad Haïdar
2016 Journal of the European Optical Society-Rapid Publications  
This letter is on the response of gallium arsenide p-i-n diodes to sub-bandgap photons (1.55 μm). We investigate the various regimes of sub-bandgap operation by using different light sources delivering pulses ranging from nanosecond to microsecond durations. We evidence two regimes : a regime of degenerate two-photon absorption, with a clear quadratic dependence with respect to the incident flux, and a sub-bandgap, temperature dependant linear regime, that drives photocurrent generation at
more » ... power densities. Both processes are associated to a very low quantum efficiency, around 10-8. We then determine absorption coefficients as well as trap densities, thanks to a model involving a photo-assisted Shockley Read Hall effect.
doi:10.1186/s41476-016-0022-8 fatcat:4iplta75ongy5lsgusfuwya5qa