Stoichiometric controlling of pulsed laser deposited boron-carbon thin films

The stoichiometry of B-C thin films was controlled via pulsed laser deposition using a series of ceramic B-C targets (B/C ratio was 3.04-5.92). The effects of B/C ratio in target, laser power and substrate-to-target distance on deposition rate, microstructure, stoichiometry and chemical structure were investigated. The maximum deposition rate was obtained at laser power of 90 mJ and substrate-to-target distance of 50 mm. Boron rich B-C films were obtained and the stoichiometry in B-C thin films was controlled in the range 2.9-4.6. Carbon atoms were bonded with only sp3 hybridization when boron was rich,but with sp2 and sp3 hybridizations when carbon was rich.