structural and optical properties of n- type porous silicon– effect of etching time

porous silicon layers have been prepared from n-type silicon wafers of (100) orientation. sem, ftir and pl have been used to characterize the morphological and optical properties of porous silicon. the influence of varying etching time in the anodizing solution, on structural and optical properties of porous silicon has been investigated. it is observed that pore size increases with etching time and attain maximum for 20 minutes and then decreases. the pl spectrum peak shifts towards the higher energy side, which supports the quantum confinement effect in porous silicon. the ftir shows that the si-hn peaks are observed at the surface of the ps layer and these chemical species also give raise the pl in ps.