ReaxFF molecular dynamics study on oxidation behavior of 3C-SiC: Polar face effects

Y Sun and YJ Liu and F Xu, CHINESE PHYSICS B, 24, 096203 (2015).

DOI: 10.1088/1674-1056/24/9/096203

The oxidation of nanoscale 3C-SiC involving four polar faces (C((1) over bar 00), Si(100), C((1) over bar(1) over bar(1) over bar), and Si(111)) is studied by means of a reactive force field molecular dynamics (ReaxFF MD) simulation. It is shown that the consistency of 3C-SiC structure is broken over 2000 K and the low-density carbon chains are formed within SiC slab. By analyzing the oxygen concentration and fitting to rate theory, activation barriers for C((1) over bar 00), Si(100), C((1) over bar(1) over bar(1) over bar), and Si(111) are found to be 30.1, 35.6, 29.9, and 33.4 kJ.mol(-1). These results reflect lower oxidative stability of C-terminated face, especially along 111 direction. Compared with hexagonal polytypes of SiC, cubic phase may be more energy-favorable to be oxidized under high temperature, indicating polytype effect on SiC oxidation behavior.

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