INTERFACE HYDROGEN BETWEEN A PB OVERLAYER AND H-SATURATED SI(111) STUDIED BY A RESONANT NUCLEAR-REACTION

Hydrogen at the interface between a Pb overlayer and a Si substrate is studied by the incident-energy dependence of the gamma-ray yield emit ted by a resonant nuclear reaction of H-1(N-15,alpha gamma)C-12. The i ncident beam of N-15(2+) at similar to 6.4 MeV is monochromatized. Whe n Pb is deposited on the Si(111)-(1 x 1)-H and Si(111)-(7 x 7)-H surfa ces, hydrogen atoms are not desorbed but remain at the interface, cont rary to Ag deposition. The origin of this difference between Pb and Ag deposition on I-I-terminated Si surfaces is discussed.