Electrical and optical characterization of porous silicon/p-crystalline silicon heterojunction diodes

The photoelectrical properties of porous silicon (PS) layers on p-type silicon were studied using two structures Au/PS/p-Si/Al (photodiode) and Au/PS/Au (photoconductor) with two different low porosity PS layer thicknesses each one. The electrical characteristics of the four fabricated devices were compared under three different light sources: a cold white lamp with an IR filter, a 465 nm blue LED and a 945 nm IR LED. Our results show a linear dependence between the measured photocurrent and the illumination power for all light sources and all studied devices. The limiting transport mechanisms in the Au/PS contact and in the PS/p-Si junction were obtained by comparing the performance of the devices.