Field-emission spectroscopy/microscopy studies of chemical-vapor-deposition-grown diamond particles

A sample for field-emission (FE) measurements was fabricated by first seedi ng high-pressure synthetic diamond particles (DPs) over a high-conductivity n-type Si(001) wafer and then growing nondoped diamond layers onto the DP surfaces by chemical vapor deposition. We have characterized several import ant features of this sample using field emission spectroscopy (FES) and fie ld emission microscopy (FEM). FES measurements showed that a FES peak start s at the substrate Fermi level and decreases in kinetic energy along with a n increase in the peak width as the electric field is increased. FEM measur ements showed that there are "hot spots" that strongly field-emit electrons . A plausible model of FE for isolated DPs on a silicon substrate is propos ed in which the key factor responsible for FE is a resistive interface betw een the DP and the substrate.