Growth and field emission properties of globe-like diamond microcrystalline-aggregate

The globe-like diamond microcrystalline-aggregates were fabricated by microwave plasma chemical vapor deposition(MPCVD) method.The ceramic with a Ti mental layer was used as substrate.The fabricated diamond aggregates were evaluated by Raman scattering spectroscopy,scanning electron microscopy(SEM),X-ray diffraction(XRD).The field emission properties were tested by using a diode structure in a vacuum chamber.A phosphor-coated indium tin oxide(ITO) anode was used for observing and characterizing the field emission.It was found that the globe-like diamond microcrystalline-aggregate exhibited good electron emission properties.The turn-on field was only 0.55V/μm,and emission current density as high as 11mA/cm2 was obtained under an applied field of 2.18V/μm.The growth mechanism and field emission properties of the globe-like diamond microcrystalline-aggregates are discussed relating to microstructure and electrical conductivity.