Electron emission from a laser ablated and laser annealed BN thin film emitter

Electron emission from a ∼100-nm-thick, laser ablated and laser annealed, carbon-doped BN film deposited on polycrystalline diamond was measured at room temperature and at pressures of about 1×10−8 Torr. For a 500-μm-diam extraction electrode, currents of several mA were obtained which corresponds to current densities of >1 A/cm2. At low currents, the current–voltage characteristics follow the classical Fowler–Nordheim behavior. At higher currents, deviations occur which are correlated to a nonlinear BN film resistance which ranges from 3×106 Ω to 5×104 Ω. For comparison, similar measurements were performed for the polycrystalline diamond film. Current densities of only 1 mA/cm2 were obtained which is attributed to a much higher sample resistance of about 1×109 Ω.