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 b een investigated by means of vibrational spectroscopy, accompanied by low e nergy electron diffraction and Auger electron spectroscopy. A faceted surfa ce consisting of the (111) face and high-Miller index face has been grown b y 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 opt ical phonons with out-of-plane displacement (TOperpendicular to) of the fil ms adsorbed on the faceted (111) and the other high-index faces, respective ly. 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 TOperpendicular to mode has appeared in the monolayer graphite on the same faceted surface. The single peak means a similar strength of the interfaci al bond on various surfaces. (C) 1999 Elsevier Science B.V. All rights rese rved.