Light-Emitting Porous Silicon Synthesized by Photoetching in Aqueous HF∕I[sub 2] Solution

We propose a new approach of porous silicon (PSi) formation using a photoetching method in a saturated solution of iodine ( I 2 ) in fluoric acid ( HF ) under Xe lamp illumination. This method enables the formation of large and homogeneous PSi layers in a very short time. Yellow photoluminescence is observed which is about 380 times stronger than that photoetched in HF solution. The surface topography as characterized by atomic force microscopy reveals features on the order of 10– 100 nm . The photoetching mechanism and related phenomena can be successfully explained with the aid of a surface energy-band diagram of n - Si in the HF ∕ I 2 electrolyte.