Field emission from as-grown and surface modified BN and CN thin films

We have investigated the electron field emission characteristics of BN and CN on highly conductive silicon thin films deposited by End-Hall ion source and electron cyclotron resonance plasma source-assisted physical vapor dep osition. The thermal processing and surface laser modification effects on t he field emission properties were investigated. Current density-field emiss ion characteristics I-eta(E) were tested in a high vacuum environment. Mg-d oped BN thin films on silicon exhibited a turn-on field as low as 25 V/mu m and a current density higher than 1 A/cm(2). The deposition of a thin BN l ayer on copper lithium (CuLi) metallic substrate yields surfaces with a 75 V/mu m onset field and a current density 1000 times higher than that obtain ed from uncoated surfaces. Under high vacuum laser annealing BN coated CuLi showed no enhancement but more stable emission characteristics. Our result s show also that pulsed ultraviolet laser irradiation of CN films in vacuum results in an increase of the field emission current densities and a reduc tion in threshold field values. The turn-on fields of the irradiated surfac es depend strongly upon the energy density of the laser beam. In addition, the electroconductivity properties of BN and CN surface mapping have been p erformed using scanning tunneling field emission microscopy. The surface to pography mapping and its correlation to the field emission properties were investigated. Preliminary results on surface mapping suggest that the surfa ce relief plays some role in field emission enhancement. (C) 1999 American Vacuum Society. [S0734-2101(99)14704-3].