Atomic-structure-dependent Schottky barrier at epitaxial Pb/Si(111) interfaces

The Schottky barrier of Pb grown epitaxially on n-type Si(111) has been studied. Two structures can be formed, which differ only in the arrangement of the first layer of Pb and Si atoms at the interface. One, a Si(111)(7×{}7)-Pb structure, has a Schottky-barrier height of 0.70 eV. The other, a Si(111)({}3 ×{} {}3 )R30^∘{}-Pb structure, has a barrier height of 0.93 eV. These results emphasize the importance of the local electronic structure for Schottky-barrier formation at ordered interfaces.