Mesoscopic elastic properties of cluster-assembled carbon films

The mesoscopic elastic response of cluster-assembled carbon films was measured by Brillouin light scattering. The values of bulk modulus and shear modulus were estimated from the shifts of both surface and bulk phonon peaks. The most basic mechanical properties of these new materials were so investigated down to the scale of a few hundreds of nanometers. The shear modulus is found in the range of that of crystalline graphite, whereas the bulk modulus and Poisson's ratio are significantly different. The results agree with the mainly sp(2) coordinated granular structure shown by Raman spectroscopy.