Abstract
Synchrotron radiation photoemission and LEED are used to probe the surface electronic structures of the Sb/Si(001)2×1 interface in a UHV chamber with a base pressure of 3×10-11 torr. The LEED patterns show that when the Sb coverage is fewer than 0.78 ML, the Sb adatoms are distributed on the Si(001) surface radomly. The surface structure remains 2×1, but gets blurred. An 1×1 structure appears clearly above 0.89 ML. Upon annealing to 300 and 500℃, the 1×1 structure becomes sharper. Further annealing to 700℃, a 2×1 structure with straeks appears The valence-band photoemission spectra show that the Sb/Si interface is semiconducting, irrespective of coverage. The saturation of the dangling bonds occurs at 0.7 ML. The binding energy of Sb-Si bond is near that of the Si-Si dimer bond, due to close their electronegativity. The Si 2p core-level photoemission spectra show that the Sb-Si interaction occurs only at the topmost Si layer. The Sb adatoms prefer to occupy the bridge site between two dimer atoms and are prone to go near the up-atom of the Si dimer. Two new states are observed with one relating to step sturctures and the other to 2×1 or c(4×4) structure.