properties of porous silicon with different acids

This paper study the characteristics of nano crystalline silicon prepared by using electrochemical etching with etching time {5,25} min for Hydrofluoric acid (HF) acid and Nitric acid (HNO3) and etching time {5,25} min for Ethanol and Hydrofluoric acid; and study the effect of this solutions on the of features porous silicon(P-Si) will use electrochemical etching for preparation from p-type silicon wafer with resistivity ( 1-10 Ω.cm ) with different time. after that, make a comparison for the morphological properties for porous silicon.