| In this paper, lots of unhydrogenated DLC films were prepared by using a KrF excimer laser at different deposited condition. By optimizing the experiment parameters, the DLC films contained more sp3 sites were obtained. The mechanical hardness and the thermal stabilities of unhydrogenated DLC films with higher sp3 contents, which are used in a wide area of industrial applications, are much superior to those of most hydrogenated DLC films. There are some points as followed:(1) The Diamond like carbon films were prepared in the different conditions. When the laser energy density decrease or the deposition temperature increase, the D peaks in Raman spectra become stronger and the optical gap become narrow. Thermal stabilities of the samples deposited at RT were better than others. The experiment results indicate that the sp2 sites increase and the clusters grow when the substrate temperature increase or the laser energy density decrease. The model of C atoms ordering was used to explain the growing mechanism.(2) The photoluminescence properties of unhydrogenated DLC films were deeply studied. The samples deposited at low temperature possess some luminescence peak in visible light. There is only one wide peak in the samples deposited at high temperature. The main band of photoluminescence shifts to short wavelength and the intensity of this band increase. The nature of localized states and the carrier recombination mechanism in the material were detail discussed. The photoluminescence can be attribute to carrier localization within an increasing sp2 clusters.(3) The nano-crystal Diamond films were prepared in proper ambient pressure oxygen gases. There is a wide 1332cm-1 peak in the Raman spectra,which indicated that, the sp content in films is high, but only some nano-crystal grain disperse on the films surface. The effects of ambient gases on the structure and properties are detail discussed. The ambient oxygen shows a strong etching sp2 effect in the growing progress. |
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