- Experimental studies of the interface between hydrogen-terminated Si(111) and evaporated Au are reported. Auger Electron Spectroscopy (AES) and Scanning Tunneling Microscopy (STM), in ambient conditions, were used to study the composition and electrical (I–V) properties of the AurSi junction, as a function of Au film thickness. Au films of 5 nm present a rectifying behavior with the tunneling current for negative tip bias. This result is explained by the fact that Si is known to migrate through the Au layer. The I–V measurements point to the fact that enough Si segregates on top of the Au layer to form a reverse diode. It is also shown that the first monolayers of gold chemically bind to the silicon. Such a surface presents electrical metallic properties at this initial stage of gold growth on silicon.