Si indiffusion on Ge(100)-(2×1) studied by core-level photoemission

Core-level photoemission spectroscopy has been utilized to study the adsorption and growth of Si on Ge(100)-(2×{}1) by molecular-beam epitaxy. The populations of Si and Ge atoms in the surface are monitored by measuring the intensities of the surface-shifted Si and Ge core-level components. After several atomic layers of Si are deposited on Ge(100) at a growth temperature of 450 C, the top layer which forms the (2×{}1) reconstruction consists of Ge atoms only. This tendency for Si atoms to move below the surface persists even for growth at about room temperature.