Field Emission from Nanocrystalline LaB{sub}6 Prepared by Laser Ablation

摘要

Pulsed Laser deposition (PLD) has been efficiently employed to get well adherent coating of nanocrystalline LaB{sub}6 on tungsten and Rhenium flats and pointed substrates. The nanocrystalline LaB{sub}6 films were analyzed by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Micro-Raman Spectroscopy, in addition to Field emission microscopy (FEM). The field emission studies of pointed specimens were performed in conventional field emission configuration, whereas for flat specimens diode configuration in close proximity was used. The Fowler-Nordheim (F-N) plot obtained from the current-voltage characteristic was found to be linear showing metallic behaviour of the emitter. The field emission current stability over a period of more than three hours is found to be good. The observed field emission characteristics of nanocrystalline LaB{sub}6 films are attributed due to the high value of the field enhancement factor, high resistance to ion bombardment and excellent structural stability against high electric field. The results indicate that the nanocrystalline LaB{sub}6 field emitter obtained by the PLD is a promising candidate for field emission based new generation devices such as microwave tubes and vacuum microelectronic devices. The results are discussed in view of the various nanomaterials studied such as Zinc oxide (ZnO), Tin oxide SnO{sub}2, Germanium/silicon (Ge/Si), Galium nitride/silicon (GaN/Si) and Aliminum nitride (AlN) nanotubes.