Roles of Ag in fabricating Si nanowires by the electroless chemical etching technique

Abstract

Silicon wafers coated with a film of Ag pattern are used for investigating roles of Ag in the fabrication of silicon nanowire arrays (SiNWs) by the electroless chemical etching technique. The diameter of SiNWs grown in the mixed AgNO3/HF solution ranges from 20 to 250 nm. A growth mechanism for such obtained SiNWs is proposed and further experimentally verified. As a comparison as well as to better understand this chemical process, another popular topic on growing SiNWs in the H2O2/HF solution is also studied. Originating from different chemical reaction mechanisms, Ag film could protect the underneath Si in the AgNO3/HF solution and it could, on the contrary, accelerate etching of the underneath Si in the H2O2/HF solution.