Field Enhancement and Work Function Difference of IrO2 Nano-Emitter Arrays using EFM and SKPM Spectroscopy
D.C.-S. Chiang, P.Z.-F. Lei, R. Barrowcliff and F. Zhang
Washington State University and Sharp Corporation, US
field enhancement factor, surface potential, EFM, SKPM,
We have measured two important physical properties related to field emission (surface potential and electric force gradient) of IrO2 nanorod emitter arrays using spectroscopy methods of electric force microscope (EFM) and scanning Kelvin probe microscope (SKPM). IrO2 nanorod arrays have been considered an outstanding material for next-generation flat panel display due to their relatively high conductivity, inertness to oxygen, and low threshold field. The spacing, radius, and morphology of the nanoprotrusions were observed to change significantly within the sample. Low-density regions yield largest, but relatively non-uniform force gradients. Relatively homogeneous force gradients were observed in areas with nanorods of smallest radius and densest population. Difference of work function is also observed between high and low density region. The discrepancy of larger than 0.5 eV of the work function may result in difference of emission current by three orders of magnitude between high density and low-density areas of the nanorod arrays.
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Nanotech 2006 Conference Program Abstract