Variation of Parameters in Metal-Assisted Catalytic Etching

Porous silicon powders were produced by Ag-catalyzed etching in an aqueous solution of HF and CH₃COOH to which H₂O₂ is injected. This research investigates how variations in the amount of Ag and H₂O₂ as well as the injection time affect metal-assisted catalytic etching (MACE). This was done by analyzing the percent yield of the product and by examining SEM images of the products before and after exfoliation of silicon nanowires (SiNW). Atomic force microscopy (AFM) analysis was also used to characterize the size and aspect ratios of the nanowires. We demonstrate that the amount of silver catalyst that was used during etching, the time of the etching, and the amount of hydrogen peroxide that was used can be used to control the structure and yield of the product of MACE.