Diamond deposition at a temperature above 1000 °C was carried out in a microwave plasma chemical vapor deposition reactor using a 3% CH4/H2 gas mixture. A polycrystalline diamond substrate was coated with a thin film of nickel in 100-nm thickness before deposition. Electron microscopy characterization of electron diffraction, high-resolution imaging, and electron energy loss spectroscopy shows that the diamonds deposited exhibit regular shapes in triangles and parallelogram with well-faceted surfaces. These diamond platelets are single crystallites with a uniform thickness of approximately 30-70 nm and length of several hundred nanometers to a few micrometers. The platelet morphology suggests that it is formed by lateral growth. Also, it was found that the diamonds are covered with a 1 to 2-nm thick graphite films in epitaxy.
- Electron energy loss spectroscopy
- Transmission electron microscopy (TEM)