ELECTRONIC STATES ON CLEAN SI(110)16X2 AND SI(110)2X3-SB SURFACES BY PHOTOEMISSION AND OPTICAL SPECTROSCOPY

The electronic properties of clean Si(110)16x2 and Si(110)2x3-Sb surfa ces have been studied by Angle Resolved Ultraviolet Photoelectron Spec troscopy (ARUPS) and Surface Differential Reflectivity (SDR). For the clean 16x2 surface four surface states have been recognized by ARUPS a nd their dispersions have been mapped along the main symmetry lines in the surface Brillouin zone. SDR experiments revealed transitions betw een filled and empty surface states at similar to 1.8, 2.4 and 2.9 eV. Antimony has been subsequently evaporated (about one monolayer) thus obtaining a 2x3 reconstruction. The surface electronic structure resul ted to be strongly modified with only two surface state bands observed in ARUPS and no optical transitions detected by SDR in our energy ran ge (1.3-3.5 eV).