Reducing the grain size for fabrication of nanocrystalline diamond films

Abstract Microwave plasma-enhanced chemical-vapor-deposited (MPECVD) diamond films grown under various bias conditions applied to the substrates have been examined by electron microscopy. It is noticed that in a certain range, increasing the bias voltage can effectively reduce the diamond grain size. Transmission electron microscopy (TEM) images distinctly reveal that the diamond films consisting of ultrafine crystallites of about 7–10 nm can be successfully fabricated by applying an appropriate bias voltage. Comparing the conventional diamond films deposited without bias and the nanocrystalline diamond films grown with a bias, one can see that the latter have better field emission properties.