Diamond films heteroepitaxially grown on platinum (111)

Abstract

Diamond films were grown by microwave plasma chemical vapor deposition on as-received platinum (Pt) foils, specially processed Pt foils with (111) domains, bulk single-crystal Pt with a (111) surface, and single-crystal Pt(111) films deposited on strontium titanate (111). In all cases, the substrate surfaces had been significantly roughened by scratching to enhance diamond nucleation. Nevertheless, it was found by scanning electron microscopy that diamond films grown on the (111) areas of the above substrates had azimuthally aligned (111) faces, where a significant spontaneous coalescence developed between neighboring faces. An observation of the diamond-Pt interface region by transmission electron microscopy indicated that diamond crystals had an epitaxial relationship with Pt, and a (111) crystal at a diamond film surface contained an extremely low density of dislocations on the order of ${10}^{8}/{\mathrm{cm}}^{2}.$ Effects of ${\mathrm{H}}_{2}$ and ${\mathrm{CH}}_{4}{/\mathrm{H}}_{2}$ plasma on a Pt surface, as well as the nucleation and growth process, were investigated in detail.