Development and characterization of porous silicon based photodiodes

Porous silicon (PS) based photodiodes have been developed from multicrystalline n+/p junctions, since this material can efficiently be employed to reduce optical reflection and to enhance absorption. These devices show a strong rectifying characteristic, in which the reverse and short-circuit current strongly depends on the presence of light. According to this, their use as solar sensors is considered as a practical application of PS-based photodiodes. The electrical performance (forward and reversed biased) of the PS-based devices under standard conditions of illumination and temperature has been determined. The angular dependence of the electrical response as a function of incidence light has also been established showing a cosine-type behavior. The degradation of these devices after extended photon irradiation as well as after long periods of atmospheric exposure has been found to be small. Finally, the variation of the electrical response under standard illumination conditions of PS-based photodetectors has also been estimated by varying the device working temperature from 10 up to 80°C.