Abstract
Atomically uniform Pb films on Ge(111) were successfully pre-pared at the thickness ranging 2-20 monolayer above dense β-phase √3×√3R30° reconstruction and measured by Angle Resolved Photoemission. The measurement of the thickness dependence of the electronic structures for Pb films on Ge(111) was performed and the peak positions of QWS were analyzed by Bohr-Sommerfeld quantization rule. The measured peak positions match the theoretically predicted values very well. The thermal stability of Pb film was studied by annealing the Pb films and measuring the thermal stability temperature. The stability temperatures exhibited a thickness-dependent oscillation with a bilayer period and beating of 9 ML. We studied lattice structure by Low Energy Electron Diffraction. Initially at 2 ML, Pb films grow in the same direction as the Ge(111) substrate. Then above 2 ML, part of Pb films grow in a new direction which was rotated 30° with respect to Ge(111) substrate. With increasing thickness, these two domains of 2D Pb islands coexist and compete with each other. The electron-electron interaction between the film and highly doped n-type Ge(111) substrate influence the formation of islands.