Surface reconstruction of Pt/Si(001)

Abstract

Platinum-induced surface reconstructions on Si( 001) were investigated by scanning tunneling microscopy. The Si( 001) surface shows c( 4 x 6) + c( 4 x 2)-type reconstruction after Pt hot deposition at 750 degrees C. The c( 4 x 2) reconstruction is formed by regular arrangement of Pt ad-atoms at the hollow sites between two Si dimers on Si( 001). The c( 4 x 6) structure is formed by long-range ordering of Si dimers superimposed on the c( 4 x 2) reconstruction. The surface reconstruction changes with the local Pt coverage and missing dimer density. An atomic model for c( 4 x 6)+ c( 4 x 2) is proposed based on the observed c( 4 x 4) surface reconstruction, a new surface reconstruction, which is observed following a high-temperature anneal at 900 degrees C. The c( 4 x 4) surface reconstruction is regular and ordered in both the dimer-row direction and the direction perpendicular to the dimer rows. The reconstruction is formed by the regular arrangement of Si dimers and Pt ad-atoms sitting on top of the hollow sites surrounded by two dimers. An atomic model for this new reconstruction is proposed.