Highly concentrated Si1-xCx alloy with an ordered superstructure.

An ordered Si-C alloy was observed in the products resulting from thermal reduction of molybdenum disilicide heating rods. High-resolution transmission electron microscopy measurements indicate that the Si1-xCx alloy with x approximately 25% is pure, single crystalline, and possesses a superlattice structure. The superlattice periodicity occurs along the diamond [001] direction and corresponds to the quintupling of the primary (002) periodicity. The possible growth mechanism is discussed. The Mo element is likely to play a crucial role in the growth process of the Si1-xCx alloy, since it can both reduce the energy required for breaking up C clusters and contribute to surface modification, which are of great benefit to enhance the carbon concentration and induce an ordered structure.