FABRICATION AND PROPERTIES OF LOW-TEMPERATURE TETRAHEDRAL AMORPHOUS-CARBON FILMS

The structural and optical properties of films of highly tetrahedral a morphous carbon obtained by dissociating a mixture of methane and argo n/hydrogen in a glow-discharge plasma at temperatures of about 300 K h as been studied. These films are optically transparent, with refractiv e indices of 1.5-2.2 and densities of 2.75-2.80 g/cm(3). The concentra tion of optically active hydrogen atoms was found to lie in the range 21-28 at. %, with a ratio of sp(3) to sp(2) bonds in the range 0.80-0. 85. The width of the optical band gap was 3.0-3.6 eV, the electronic m obility was similar to 2 cm(2)/(V . s), and the resistivity was 0.01-1 0(-12) Omega . cm. A broad band in the photoluminescence spectra with a maximum at wavelengths 487-493 nm and a halfwidth of 60-80 nm has be en observed. (C) 1996 American Institute of Physics.