Field emission cathodes are being considered for use on low-power electrostatic and electromagnetic propulsion systems as well as on electrodynamic tether systems. In these systems, field emission cathodes prevent negative spacecraft charging by emitting a lowpower electron beam that is accommodated by the ambient plasma. Prototype cathodes were tested at the University of Michigan as part of a...

The merit of various kinds of carbon nanotubes as field electron emission cathode materials has been studied. The field electron emission characteristics of electrophoretically deposited films of single walled carbon nanotubes, multiwalled carbon nanotubes of diameter between 10 and 20 and .50 nm and carbon nanofibres with diameters between 200 and 600 nm were investigated. Results of the measu...

Vertically aligned SnO2 nanowire arrays have been in situ fabricated on a silicon substrate via thermal evaporation method in the presence of a Pt catalyst. The field emission properties of the SnO2 nanowire arrays have been investigated. Low turn-on fields of 1.6 to 2.8 V/μm were obtained at anode-cathode separations of 100 to 200 μm. The current density fluctuation was lower than 5% during a ...

We report the electrical characterization and field emission properties of MoS 2 bilayers deposited on a SiO 2 / Si substrate. Current-voltage characteristics are measured in the back-gate transistor configuration, with Ti contacts patterned by electron beam lithography. We confirm the n-type character of as-grown MoS 2 and we report normally-on field-effect transistors. Local characterization ...

Field Emitter Arrays (FEAs) are being developed for electron emission in electrodynamic tether applications. Instead of a single hot (i.e. high powered) emitter or a gas dependant plasma contactor, FEA systems consist of many (up to millions per square centimeter) of small (micron-level) cathode/gate pairs on a semiconductor wafer that effect cold emission at a relatively low voltage. Each indi...

Field emission cathodes are presently being developed as low-power space electric propulsion neutralizers and for spacecraft charge control and electrodynamic tether applications requiring no consumables. These cathodes effect cold electron emission by the application of a relatively high electric field across a small gap from some kind of electron emitting (cathode) surface. Various designs of...

The influence of the different types of bonding present in a range of carbon based materials is discussed as a precursor to describing the field emission characteristics of carbon cold cathode materials. Some of the controlling factors which govern electron emission from carbon based cathodes are discussed. It is shown that from disordered carbon films the interplay between the clustered sp 2 p...

We report the electrical characterization and the field emission properties of CVD-grown 12 bilayers deposited on / substrate. Current-voltage characteristics are measured in the 13 back-gate transistor configuration, with contacts patterned by electron beam lithography. We 14 confirm the n-type character of as-grown and we report normally-on field effect transistors. 15 Local characterization ...

The origin of low threshold field-emission (threshold field 1.25 V/μm) in nanocrystalline diamond-like carbon (nc-DLC) thin films is examined. The introduction of nitrogen and thermal annealing are both observed to change the threshold field and these changes are correlated with changes to the film microstructure. A range of different techniques including micro-Raman and infrared spectroscopy, ...