Simultaneous growth of diamond and nanostructured graphite thin films by hot-filament chemical vapor deposition

Diamond and graphite films on silicon wafer were simultaneously synthesized at 850 °C without any additional catalyst. The synthesis was achieved in hot-filament chemical vapor deposition reactor by changing distance among filaments in traditional gas mixture. The inter-wire distance for diamond and graphite deposition was kept 5 and 15 mm, whereas kept constant from the substrate. The Raman spectroscopic analyses show that film deposited at 5 mm is good quality diamond and at 15 mm is nanostructured graphite and respective growths confirm by scanning auger electron microscopy. The scanning electron microscope results exhibit that black soot graphite is composed of needle-like nanostructures, whereas diamond with pyramidal featured structure. Transformation of diamond into graphite mainly attributes lacking in atomic hydrogen. The present study develops new trend in the field of carbon based coatings, where single substrate incorporate dual application can be utilized.

Diamond and nanostructured graphite was deposited in single run experiment over single substrate in hot-filament CVD reactor by varying filament’s distances. The substrate portion over which the 15 mm filament’s distance, nanostructured graphite is deposited and the substrate portion over which the 5 mm filament’s distance, diamond structure is deposited. The dedicated regions for both diamond and graphite are indicated in the schematic of hot-filament CVD reactor.Figure optionsDownload as PowerPoint slide