Response of a Silicon Photodiode to Pulsed Radiation
Robert E. Vest, Steven E. Grantham
Both the integrated-charge and peak-voltage responsivity of a 1 cm2 Si photodiode optimized for the extreme ultraviolet have been measured with 532 nm wavelength pulsed radiation. The peak power of the optical pulse is varied from 35 mW to 24 kW with a pulse width of 8.25 ns. A decrease in responsivity is observed with increasing pulse energy, and a model is presented that accounts for the observed loss of responsivity. The integrated-charge responsivity decreases because the presence of photogenerated majority carriers increases the direct recombination rate. The peak-voltage efficiency is reduced because the electric susceptibility of the electrons and holes in the depletion region increases the capacitance of the device. The influence of an applied reverse bias on both responsivities is determined. The integrated-charge responsivity is found to be identical, with 1% uncertainty, to the cw responsivity of the device if the energy dependence is considered.