Hydrogen at the surface and interface of metals on Si(111)

The depth-resolved measurement of hydrogen using the resonant nuclear reaction of ¹H(¹⁵N,αγ)¹²C in the formation of (Pb, Ag, and Cu)/Si(111) interfaces is reported. It was found that Pb deposition on Si(111)1×1-H at 110 and 360 K leads to the formation of the Pb/H/Si(111) interface. Upon deposition of Ag at 110 K, however, it was found that a quarter of the monolayer of H migrates to the surface of Ag with the rest of H remaining at the Ag/Si(111) interface. The preadsorbed H atom was desorbed from the surface by deposition of Ag and Cu at 360 K, suggesting that (Ag, Cu)/H/Si(111) is a metastable structure. The relative stability of the interface H is discussed.