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The effects of chemical bonding states on the electrical properties of hydrogen-free amorphous carbon nitride (a-CN x ) films were reported. a-CN x films were prepared by reactive RF magnetron sputtering at various deposition temperatures. The electrical conductivity of the a-CN x films increased with increasing deposition temperature because of the predominant sp 2 C-C bonding sites. Their conductivity increased by almost one order of magnitude with a 25% decrease in the fraction of the N-sp 3 C bonding state. It was found that the fraction of the N-sp 2 C bonding state strongly contributed to the increase in the electrical conductivity. Nitrogen incorporation led to an increase in the sp 3 C-C bonding fraction in the films; as a result, the conductivity of the a-CN x films was found to be lower than that of the a-C films deposited under the same conditions.

A series of shock-recovery experiments on a single crystal of silicon up to 38 GPa and characterizations of the recovered samples by x-ray diffraction analysis, Raman spectroscopy, and microscopic observations were performed for a better understanding of residual effects after shock loading by using a propellant gun. The x-ray diffraction trace of each sample revealed the absence of additional constituents including metastable phases and high-pressure phases of silicon except for 11 and 38 GPa. At 11 GPa, small amounts of metastable phases of silicon were obtained. The formation of copper silicide (Cu3Si) was confirmed in the sample shocked at 38 GPa. Considering the surface morphology revealed by microscopic observation, a thermochemical reaction through the melting of silicon resulted in the formation of Cu3Si. An additional band and the center frequency deviation of a peak were shown in the Raman spectroscopy results. The results of x-ray diffraction and Raman spectroscopy indicated that crystalline size reduction rather than the formation of metastable phases occurred. Structural deformation rather than the thermal effect caused by a shock-induced temperature rise may be responsible for the disappearance of metastable phases, which were observed in other high-pressure experiments.

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