Fabrication and analysis of conductive channels in diamond- like amorphous carbon films

Amorphous carbon films have attracted much interest because their physical properties can be tuned by changing deposition conditions. In many device applications, we need heterostructures composed of carbon films of different properties. This can be achieved for example by depositing different carbon film types using conventional lithography. Alternatively, we can create heterostructures through the use of energetic particle beam to directly modify an otherwise homogeneous film. Here we report an example of the latter by the creation of conductive channels in an amorphous diamond-like carbon films using either high-energy electron beams or uranium ion beams. The modified structures are characterized by atomic force microscopy and electron energy loss spectroscopy. The conductive channels in both cases are found to be regions rich in sp(2) bonded atoms.