Vibrational spectra of the monolayer films of hexagonal boron nitride and graphite on faceted Ni(755)

Hexagonal boron nitride (h-BN) and graphite films on faceted Ni(755) have been investigated by means of vibrational spectroscopy, accompanied by low energy electron diffraction and Auger electron spectroscopy. A faceted surface consisting of the (111) face and high-Miller index face has been grown by the adsorption of monolayer films. Vibrational spectra of the monolayer h-BN have exhibited two peaks at 90 and 97 meV, which originate from the optical phonons with out-of-plane displacement (TO(perpendicular to)) of the films adsorbed on the faceted (111) and the other high-index faces, respectively. These peaks indicate that the bond strength between h-BN films and a Ni face depends on the Ni face orientation. On the contrary, only one peak of TO(perpendicular to) mode has appeared in the monolayer graphite on the same faceted surface. The single peak means a similar strength of the interfacial bond on various surfaces. (C) 1999 Elsevier Science B.V. All rights reserved.