A novel gas field ionization ion source based on printed carbon nanotubes thin-film

We developed a novel gas field ionization ion source based on printed carbon nanotubes (CNTs) thin film and measured the field ionization characteristics with various gases including argon, nitrogen and hydrogen under different pressures in the high-pressure chamber. We achieved a collector current as high as 6.8 nA (the corresponding local field was 14.9 V/nm) at 0.6 mTorr hydrogen pressure, resulting in a current density of 0.87 μA/cm². The result show that the ratio of the threshold field in ion emission for various gases is mainly related to differences in ionization energy, and is roughly agrees with well-characterized previous work in field ion microscopy.