Initial stage of Au adsorption onto a Si(111) surface studied by scanning tunneling microscopy

The initial stage of Au adsorption onto a Si(111) surface (<0.2 ML) is studied by scanning tunneling microscopy (STM). Au is deposited at room temperature, and then the sample is annealed at 700 °C. At the very early stage of Au adsorption, a Au-adsorbed 5× structure is found not to break a 7×7 structure. By increasing the amount of adsorbed Au, the Si substrate itself shows a 5× structure. Rows of the Au-adsorbed 5× structure are observed to have grown from the lower side of steps.