Evolution of the morphology of diamond particles and mechanism of their growth during the synthesis by chemical vapor deposition

The evolution of the surface morphology of diamond particles synthesized by chemical vapor deposition (CVD) on silicon substrates has been investigated. It has been found that, when the diamond particles reach a critical size of less than 800 nm, the surface of the diamond faces is transformed. Particles with sizes of no more than 100–300 nm have a well-faceted surface covered by the $\{100\}$ and $\{111\}$ faces. An increase in the size of diamond particles leads to a change in the structure of their surface. The surface is covered by the $\{100\}$ faces surrounded by a disordered phase. With a further increase in the particle size (up to $\sim$ 2000 nm), the $\{100\}$ faces disappear and the diamond particles are covered by high-index faces. A model explaining the evolution of the surface morphology of diamond particles has been proposed. According to this model, during the evolution of diamond particles with an increase in their size, the mechanism of layer-bylayer growth changes to normal growth, which leads to a significant transformation of the entire surface of the diamond particles. The critical size of a two-dimensional nucleus formed on the $\{100\}$ and $\{111\}$ faces, at which the change in the growth mechanism begins to occur, has been calculated. A method has been proposed for controlling the morphology of diamond particles during their synthesis.