HYDROGEN CONCENTRATION AND MASS DENSITY OF DIAMOND-LIKE CARBON-FILMS OBTAINED BY X-RAY AND NEUTRON REFLECTIVITY

Specular reflectivity of neutrons and x rays can be used to determine the scattering length density profile of a material perpendicular to i ts surface. We have applied these techniques to study amorphous, diamo ndlike, hydrocarbon films. By the combination of these two techniques we obtain not only the mass density, but also the concentration of hyd rogen, which varies in our case between 0 and 30 at.%. This method is a new and nondestructive way to determine the concentration of hydroge n within an error of less than 2 at.% in samples with sharp interfaces . It is especially suited for diamondlike carbon films.