Model Semiconductor Surfaces: Arsenic Termination of the Ge(111), Si(111) and Si(100) Surfaces

Recent results for the arsenic termination of the Ge(111), Si(111) and Si(100) surfaces are reviewed. Arsenic interaction with the Ge(111) and Si(111) surfaces has been found to result in the replacement of the outer Ge (Si) layer with an As layer. This arrangement has a 1 × 1 symmetry and the calculated positions of the As atoms are very close to the positions expected from bulk bond lengths. Ge(111): As and Si(111): As thus provide us with model ideal surfaces. Similar investigations of the Si(100): As 2 × 1 surface show that this system can be considered as a model for surface dimers. Experimental surface-state dispersions obtained from angle-resolved photoemission measurements and their comparison with results of total energy calculations for these surfaces are reviewed. Photoemission core level data for the As-terminated surfaces and for GaAs on Si(111) are also discussed in terms of the model surfaces.