Molecular dynamics simulations based on Tersoff's empiricalpotential were performed and the atomic distribution in a-Si_(1-x)C_xalloys, for x=0, 0.25 and 0.5 was computed. The results show thatonly the modified potential enables to provide correct samplestructures containing the maximal number of four-fold coordinatedatoms. All the samples of 64, 216 and 512 atoms have an abnormalcoordination predominantly due to five-coordinated silicon atoms,though several three- fold coordinated carbon and silicon atoms werefound in large sized samples. Pair Si-Si correlations are diffuse,therefore the number of abnormally coordinated silicon atoms dependson a cut-off distance and cannot be defined precisely. For C atoms,we found about 15/100 of homonuclear bonds. The obtained results arecompared with available structural pictures of amorphous siliconcarbide alloys.
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