Characterization of Au/PS/p-Si heterojunction

The porous silicon (PS) layers were formed on p-type silicon (Si) wafer. The samples were anodized electrically with 50 mA/cm(2) fixed current density for different etching times. The structural properties of porous silicon on silicon substrates were investigated by photoluminescence (PL). The band gap of the samples was measured through the photoluminescence (PL) peak. It shows that band gap value increases by raising the porosity. Photodiodes of the Au/PS/p-Si/Al was performed. I-V characteristics shows that the maximum efficiency of this system is at etching time=30min (eta=0.32) while at 10min the efficiency drop (0.08). The C-V characteristics were measured, and it was found within the range V-bi=0.2-1.5 Volt at different frequencies and etching time. The results show a strong influence of the etching time parameters on kinetic changes of the device's electrical properties.