J. Physique Lett. 39, 287-290 (1978)
DOI: 10.1051/jphyslet:019780039016028700

Electronic and crystallographic structures of silver adsorbed on silicon (111)

J. Derrien¹, G. Le Lay¹ et F. Salvan<sup>2

1</sup>  Centre de Recherche des Mécanismes de la Croissance Cristalline, CNRS. Universités Aix-Marseille et . Centres de Luminy et de St-Jérôme, 13288 Marseille Cedex 2, France
²  Groupe de Physique des Etats Condensés, ERA 373 CNRS. U.E.R. Scientifique de Luminy. Université Aix-Marseille , 13288 Marseille Cedex 2, France

Abstract
We show, in this letter, direct relations between the electronic properties of the Ag/Si(111) system as investigated by low energy electron loss spectroscopy (ELS), and the silver growth process as monitored with electron diffraction (LEED, RHEED and TEM) and Auger electron spectroscopy (AES). At room temperature, where two-dimensional (2D) epitaxial layers are formed, the ELS spectra reveal almost bulk-silver-like transitions for metal overlayer coverage as low as θ ˜ 3. At high temperatures (> 200 °C), where three-dimensional (3D) growth occurs after completion of a first ordered layer, the ELS spectra are similar to those of bulk-silver, but only for high coverage (θ >≈ 30). We discuss also the physical origin of the Ag ELS peaks observed in thin films.

Résumé
On montre que la méthode des pertes d'énergie d'électrons lents est très sensible au mécanisme de croissance des atomes sur un substrat solide, sous ultra-vide. Appliquée à l'interface argent-silicium, cette méthode révèle des spectres des pertes d'énergie différents selon que l'argent forme un film bidimensionnel continu (basse température) ou un film discontinu de cristallites tridimensionnelles (haute température).

PACS
6855 - Thin film growth, structure, and epitaxy.
7320H - Surface impurity and defect levels: energy levels of adsorbed species.
7330 - Surface double layers, Schottky barriers, and work functions.
7340N - Electrical properties of metal nonmetal contacts.
7920F - Electron surface impact: Auger emission.
7920K - Other electron surface impact phenomena.
2530D - Semiconductor metal interfaces.

Key words
adsorbed layers -- Auger effect -- electron energy loss spectra -- elemental semiconductors -- interface electron states -- low energy electron diffraction -- metallic epitaxial layers -- metallic thin films -- reflection high energy electron diffraction -- Schottky effect -- semiconductor metal boundaries -- silicon -- silver -- transmission electron microscope examination of materials -- crystallographic structures -- Schottky barrier formation -- low energy electron loss spectroscopy -- ELS -- electron diffraction -- LEED -- RHEED -- TEM -- Auger electron spectroscopy -- AES -- adsorbed Ag -- electronic structure -- Si 111 -- two dimensional epitaxial layers -- three dimensional clusters