کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5368327 | 1388390 | 2007 | 4 صفحه PDF | دانلود رایگان |

The plasma produced by laser ablation of a graphite target was studied by means of optical emission spectroscopy and a Langmuir planar probe. Laser ablation was performed using a Nd:YAG laser with emission at the fundamental line with pulse length of 28Â ns. In this work, we report the behavior of the mean kinetic energy of plasma ions and the plasma density, as a function of the laser fluence (J/cm2), and the target to probe (substrate) distance. The characterized regimes were employed to deposit amorphous carbon at different values of kinetic energy of the ions and plasma density. The mean kinetic energy of the ions could be changed from 40 to 300Â eV, and the plasma density could be varied from 1Â ÃÂ 1012 to 7Â ÃÂ 1013Â cmâ3. The main emitting species were C+ (283.66, 290.6, 299.2 and 426.65Â nm) and C++ (406.89 and 418.66Â nm) with the C+ (426.65Â nm) being the most intense and that which persisted for the longest times. Different combinations of the plasma parameters yield amorphous carbon with different structures. Low levels (about 40Â eV) of ion energy produce graphitic materials, while medium levels (about 200Â eV) required the highest plasma densities in order to increase the CC sp3 bonding content and therefore the hardness of the films. The structure of the material was studied by means of Raman spectroscopy, and the hardness and elastic modulus by depth sensitive nanoindentation.
Journal: Applied Surface Science - Volume 254, Issue 1, 31 October 2007, Pages 185-188