Amorphous diamond like carbon films as a new material for electron devices

Thin films of a:DLC were deposited by plasma decomposition of hydrocarbon gas, such as methane (CH/sub 4/). The plasma was produced using an r.f. generator (13.56 MHz) at room temperature. The a:DLC structure was optically studied in the visible light. The optical measurements show an optical band gap of about 0.96 eV and refractive index (n) of 1.7-2.2 in visible light range. Microhardness test shows high hardness of about 4700 kg/mm/sup 2/ for pure a:DLC, but the microhardness of the films is being reduced with nitrogen concentration in the deposition process. The electrical resistivity of the films is reduced by 3 orders of magnitude with nitrogen incorporation. Photoconductivity measurements were performed on an Al-a:DLC-Cu sandwich structure. A photocurrent signal of 100 times higher than the dark current was measured under He-Ne laser incident light (2.5 mW) at -130C substrate temperature.