Field Emission Behaviour of Single-Crystal Pd Nanowires

Single-crystal Pd nanowires with typically 100 nm diameters and lengths from several micrometers to tens of micrometers were grown on Al2O3substrates in a furnace with Ar atmosphere. Integral field emission measurements of such samples after Pd coating (~10 nm) were performed in a diode configuration with a 50 $\mu\mathrm{m}$ mica spacer in a vacuum chamber at pressures of about 10–9 mbar. The IV measurement of the sample shows an integral emission current up to 2 $\mu \mathrm{A}$ at a voltage of 500 V (10 MV/m) and an onset voltage for a current of 1 nA of about 275 V. The corresponding Fowler-Nordheim plot show a linear behavior, like expected for a metal needle.