Nanocrystalline films were deposited onto molybdenum foil using the pulsed laser deposition technique. The as-deposited films were characterized by X-ray diffraction, scanning electron microscopy and atomic force microscopy. X-ray diffraction patterns revealed the cubic crystallinity of the film. Atomic force microscopy studies revealed that the conical-shaped nanostructures had a height of 60nm, base of 800nm and a typical radius of curvature of ∼20nm. A comparison of force and in situ current imaging atomic force microscopy studies revealed that current contrast did not originate from the surface topography of the film. Field emission studies were performed in the planar diode configuration. A current density of 4.4 x 10-2A/cm2 was drawn from the actual emitting area. The Fowler-Nordheim plot was found to be linear, in accordance with a quantum mechanical tunneling phenomenon. The field enhancement factor was estimated to be 3585, indicating that the field emission was from LaB6 nanocrystallites present on the emitter surface, as confirmed by the atomic force microscopy. The emission current-time plots revealed current stability to the extent of 5% fluctuation about the average current over a period of 3h.

Some Aspects of Pulsed Laser Deposited Nanocrystalline LaB6 Film: Atomic Force Microscopy, Constant Force Current Imaging and Field Emission Investigations. Late, D.J., Date, K.S., More, M.A., Misra, P., Singh, B.N., Kukreja, L.M., Dharmadhikari, C.V., Joag, D.S.: Nanotechnology, 2008, 19[26], 265605