Enhanced control of diamond nanoparticle seeding using a polymer matrix

We have improved the diamond nanoparticle seeding approach for chemical vapor deposition diamond growth in a novel process that consists of embedding the nanoparticles into a polymer matrix. We used a thin film of polyvinyl alcohol (PVA) doped with nanoparticles, which burns away during the initial stages of growth, leaving a stable distribution of nanoparticles on the substrate to initiate growth. The study shows that by varying the initial concentration of nanoparticles in the polymer preparation, it is possible to control the density of nanoparticles on the surface, over a wide range of densities. In some experimental conditions, the high densities of diamond seeding values obtained compare well with the highest values reported by the state-of-the-art. Moreover, the technique also opens up the route to very large area seeding, and this onto most types of substrates. In situ x-ray photoelectron spectroscopy (XPS) analyses showed that after pyrolysis of the polymer under H 2 plasma, no significant residual carbon from the polymer was observed. Also, in the case of growth on silicon substrates, no silicon carbide was observed at the surface, showing that no reaction takes place between the polymer and the silicon surface itself. Finally, XPS also demonstrated that the polymer has not modified significantly the surface of the diamond nanoparticles after its pyrolysis. This approach improves the reproducibility of diamond nanoparticle seeding on flat surfaces and is more versatile as it may be applied to complex three-dimensional structures or cavities.