Electroless deposition of Au nanocrystals on Si(111) surfaces as catalysts for epitaxial growth of Si nanowires

Abstract

Au nanocrystals were prepared by reacting solutions containing NaAuCl4 2 H2 0 with hydrogen-terminated silicon (111) surfaces. The nanocrystals catalyze the subsequent growth of silicon nanowires by chemical vapor deposition using a mixture of SiH4 and HCl in a H2 ambient. Depositing the metal nanocrystals from nonaqueous solutions, such as ethanol, minimizes the oxidation of Si that can occur in an aqueous solution and allows epitaxially aligned growth of the nanowires. The Au nanocrystals preferentially deposit onto hydrogen-terminated Si(111) compared to silicon dioxide. This selective deposition allows positioning of nanocrystals on patterns formed using either conventional lithography or nanoimprint lithography. © 2006 The Electrochemical Society.