QUANTUM-SIZED AU STRUCTURES ON SI(111) STUDIED BY SPECTROSCOPIC ELLIPSOMETRY

Spectroscopic ellipsometry has been used to follow the initial stages of the growth of Au on both singular and vicinal Si(lll) surfaces. The imaginary part of the pseudo dielectric function shows an distinctive sharp peak at 2.7 eV, at the point where the single-domain pseudo-5 x 1 low energy electron diffraction pattern is strongest for Au growth on the stepped Si(lll) surface. The singular system behaves differentl y. The unusual optical behaviour of the Au-induced 5 x 2 reconstructio n is attributed to the recently-discovered quasi one-dimensional elect ronic structure of this system.