Field emission from gadolinium silicide prepared by ion implantation with electron beam annealing

A silicon-based field emission cathode, the rare earth silicide GdSi2 was prepared by implanting Gd ions into silicon using a metal vapor vacuum arc ion source and subsequently annealed by electron beam. For as-implanted samples, turn-on field was about 21 V/mu m at a current density of 1 mu A/cm(2) and a field emission current density of 1 mA/cm(2) was reached at an applied field of 34 V/mu m. After annealing, the turn-on field could be as low as 9 V/mu m and the current density of 1 mA/cm(2) can be reached at an applied field of 14 V/mu m. X-ray diffraction with x-ray photoelectron spectroscopy analyses and atomic force microscopy were used to characterize microstructure changes of the samples. The results showed that these excellent field emission characteristics were attributed to the GdSi2 compounds formed in the samples. The field emission mechanism was discussed in terms of Fowler-Nordheim (FN) theory. It was found that FN plots could be divided into two segments obviously, and this was perhaps because of the thermal effect in the process of field emission. (c) 2007 American Institute of Physics.