GROWTH AND CHARACTERIZATION OF NANO STRUCTURED COMPOSITE CARBON FILMS

Abstract

The structural and surface morphology of metal-incorporated diamond like carbon films have been investigated. These films were deposited on Si (111) substrates using Pulsed Laser Deposition (PLD) technique. A KrF Excimer laser (λ= 248 nm) was used for co- ablation from multi component Ni-graphite and Ag-graphite targets. The carbon composite films were prepared without and with external magnetic field applied transverse to the plume. The structural analysis was performed using X-ray Differactrometer (XRD) and Raman spectroscopy. Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM) analyses were performed to explore the surface morphology, texture and roughness of films. The application of external magnetic field has significantly improved the film quality. Films prepared in the presence of external magnetic field have comparatively larger crystallite size of Ni as well as of Ag. Another important aspect of application of external field is the enhancement in the graphitization and shifting of G-band towards higher wave number. The nucleation and growth process of carbon films are strongly dependent on the size and energies of the ablated species. The I D /I G ratios for the films prepared under external magnetic field indicate that the chain length and the six-fold aromatic rings of carbon clusters have developed substantially in that film matrix and thus graphitization is enhanced. The metal intercalated atoms support to the formation of carbon ring clusters by taking the π-electron which reduces the excited state of molecule. The surface morphological investigations reveal that surface texture and organized growth of the particles varies with concentration as well as with the applied field. The roughness has also been influenced by the application of magnetic field as well as by the Ni and Ag dopants in the prepared composite films. The purpose of developing such kind of films is to enhance the conventional properties of the films and to achieve some exceptional results which are not possible in ordinary films. These films have a vast variety of applications in photo-voltaic, bio-medical, tribological and semiconductor industry.