Field emission investigation of boron doped diamond thin films synthesized by microwave plasma chemical vapor deposition: Effect of vacuum annealing

Boron-doped nanodiamond (NCD) films were synthesized on silicon substrates by microwave plasma chemical vapor deposition (MPCVD) technique. The effect of vacuum annealing on the field emission characteristics of NCD films has been investigated. The surface morphology and quality of films was characterized by scanning electron microscope (SEM) and Raman spectroscopy. The SEM images clearly reveal formation of nanocrystalline diamond (NCD) on the entire substrate surface. The Raman spectra of the as-synthesized films and films annealed at different temperatures in vacuum showed the characteristics peaks at ~1140, 1350 and 1480 cm
^-1
confirming the nanocrystalline nature of the diamond crystallites. The field emission properties of NCD films were enhanced by the rapid annealing process. The threshold fields of thermal treated boron doped NCD film are observed to be low as compared to as grown. The enhanced field emission properties may be attributed to the atomic defects created due to annealing, which play active role in the emission mechanism.