Study of the Properties of the Porous Silicon Synthesized by Ag Assisted Chemical Etching

Porous Silicon (PSi) is synthesized by Ag assisted electroless etching and characterized by Scanning electron microscopy (SEM). The effect of etching time on the optical reflectivity, optical absorbance of PSi is investigated. Reflectivity measurements showed that 45% reflectivity Si wafers drops from 45% to 10% for 2 hours etching and 6% for 3 hours etching. The decrease in the reflectivity shows that the PSi can be employed as an anti reflecting substrate in optoelectronic devices. The absorbance measurements reveal that the average absorbance of PSi is 0.60 in the wavelength range 300-800 nm after 2 hours etching. From the photoluminescence spectra it was found that PL intensity of PSi is high compared to bare silicon wafer. Static water contact angle measurements were performed to examine the hydrophobic properties of the PSi prepared under different conditions.