Dehydrogenation of C₂H₄absorbed on Si(111)7 × 7 surfaces

Abstract

Using HREELS it has been shown that C2H4 associatively adsorbs on Si(111)7 × 7 at room temperature. From a comparison of data obtained for specular reflection with those obtained for specular reflection with those obtained for off-specular reflection it is assumed that the molecule absorbs in a flat-lying position. Thermal processing leads to dehydrogenation with the hydrogen occupying free on-top sites above 180 degrees C. Above 390 degrees C hydrogen desorbs. Annealing to temperatures above 490 degrees C leaves behind only carbon on the surface in an adsorbed configuration, this changes into a carbide-like configuration after annealing to higher temperatures.