TEM simulation of nano-structured carbon films

Carbon films prepared by specially modified laser induced vacuum deposition (Laser-Arc) show a nano-heterogeneous structure with graphitic inclusions embedded in an amorphous diamond-like carbon matrix. Based on TEM investigations several different three-dimensional geometries have been suggested for theses inclusions. By using the multislice method of the EMS-program, the electron imaging of these variants (spheres, cylinders, screws) has been simulated. The TEM simulations show the large influence of 1) even small inclinations and 2) of the surrounding amorphous matrix on the visibility of the graphitic lamellae. These findings explain the experimental observations of large contrast differences in top view and cross sectional images, and of preferred contrast at ultrathin sample areas.