Effect of annealing temperature on the structure of diamond-like carbon films by electrodeposition technique

Diamond-like films have been prepared by electrodeposition in liquid phase. The films consist of a little amount of hydrogen, which can be removed by annealing at below 600°C. The Raman signal of annealing films suggested: (1) the intensity ratio I_D/I_G increases which suggested that the crystallites grew in number and size with increasing temperature; (2) the D-line position changes from 1380 to 1346 cm^-1, and the G-line position from 1580 to 1604 cm^-1 which indicated that partially tetrahedral bonds have been broken and have transformed to trigonal bonds, (3) the linewidths of the D and G-line decrease with the increasing annealing temperature. These results indicated that the primary bonding in the films changed gradually from sp³-bonded to sp²-bonded carbon with increasing annealing temperature, i.e., graphitization.