Field emission from HfC films on Mo field emitter arrays and from HfC arrays

Summary form only given, as follows. Mo FEAs as well as individually fabricated Mo field emitters were dosed via PVD from a high-purity HfC source. The deposited film was subjected to a variety of heating treatments, followed by FEM examination and determination of I-V characteristics. The results of these experiments indicate that work function reductions of the order of 1 eV can be achieved. The observed FEM patterns indicate that the lowest film work functions occur on and around the (100) planes of the underlying Mo emitter. We also report on our continued experiments with HfC film deposition onto Mo field emitter arrays. In the case of HfC on a Spindt array of Mo cathodes we observed a typical decrease of operating voltage from 121 V to 74 V for 1000 /spl mu/A emission current following HfC deposition. These results seem consistent and very promising for the use of HfC films on field emitters and field emitter arrays. Preliminary work is also reported on the formation of emitting cones by deposition of HfC directly into array blanks. This procedure may be able to provide increased emission stability compared with HfC films on Mo cones.