Fabrication of nano-sized platinum particles self-assembled on and in CVD diamond films

We have investigated in detail the structures of nano-sized sphere-like platinum particles self-assembled on and in chemicalvapor- deposited (CVD) diamond. The Pt particles were transformed from Pt thin films deposited on various diamond substrates after hydrogen microwave plasma irradiation orCVDdiamond overgrowth. This structural change of the Pt filmswas found to be a kind of hydrogen catalytic effect and to depend on the Pt filmthickness and the treatment temperature. The average diameter of the self-assembled Pt particles waswell controlled by changing thickness of the Pt film deposited on the diamond substrate. Especially, the Pt particles with diameters less than 10 nm were analyzed by means of a transmission electron microscope, and were found to be single-crystalline in structure. Furthermore, electron diffraction data of the Pt particles evidenced an expansion of the Pt lattice.