Formation and stability of a two-dimensional nickel silicide on Ni(111): An Auger, LEED, STM, and high-resolution photoemission study

B. Lalmi (1, 2) , C. Girardeaux (3) , A. Portavoce (3) , C. Ottaviani (4) , B. Aufray (5) , J. Bernardini (6)

1 LENAC - Laboratoire d'Electronique, Nanotechnologies, Capteurs
2 LPN - Laboratoire de photonique et de nanostructures
3 IM2NP - Institut des Matériaux, de Microélectronique et des Nanosciences de Provence
4 ISM - Instituto di Struttura della Materia
5 CINaM - Centre Interdisciplinaire de Nanoscience de Marseille
6 L2MP - Laboratoire matériaux et microélectronique de Provence

Using low-energy electron diffraction (LEED), Auger electron spectroscopy (AES), scanning tunneling microscopy (STM), and high-resolution photoelectron spectroscopy (HR-PES) techniques we have studied the annealing effect of one silicon monolayer deposited at room temperature onto a Ni (111) substrate. The variations of the Si surface concentration, recorded by AES at 300 degrees C and 400 degrees C, show at the beginning a rapid Si decrease followed by a slowing down up to a plateau equivalent to about one third of a silicon monolayer. STM images and LEED patterns, both recorded at room temperature just after annealing, reveal the formation of an ordered hexagonal superstructure of (root 3 x root 3)R30 degrees type. From these observations and from a quantitative analysis of HR-PES data, recorded before and after annealing, we propose that the (root 3 x root 3)R30 degrees superstructure corresponds to a two-dimensional Ni2Si surface silicide.

Domains: Physics [physics]; Condensed Matter [cond-mat]; Materials Science [cond-mat.mtrl-sci]

B. Lalmi, C. Girardeaux, A. Portavoce, C. Ottaviani, B. Aufray, et al.. Formation and stability of a two-dimensional nickel silicide on Ni(111): An Auger, LEED, STM, and high-resolution photoemission study. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2012, 85 (24), pp.245306. ⟨10.1103/PhysRevB.85.245306⟩. ⟨hal-02385394⟩