Growth of silicon and germanium on Cu(111) studied by angle-resolved direct and inverse photoemission

The growth of evaporated silicon and germanium on Cu(111) has been studied by angle-resolved direct and inverse photoemission. At room temperature both semiconductors form a reacted interface a few angstroms thick. For overlayers of more than 20- thickness the surface-sensitive photoemission techniques demonstrate the growth of pure silicon or germanium films. Annealing of thin films (<5) of Si on Cu(111) results in a uniformly reacted interface with a (3 × ) R30°low-energy electron diffraction (LEED) pattern, while annealing of Ge films results in a 1×1 LEED pattern. The dispersion of two unoccupied surface states of the annealed Ge film is determined by angle-resolved inverse photoemission. Based on our photoemission results, a description of the chemical reaction in the semiconductor-on-metal interface is presented. © 1990 The American Physical Society.