4589.1:
Carbon Nanotubes as Efficient Electron Sources
Abstract
The subject of this project is to explore the possibilities of using carbon nanotubes (CNT’s) as thin film electron field emitters. Toady’s thermionic emitters have to be operated at temperatures ranging between 950° and 2200° C, which makes their use in micron sized devices impossible due to high energy consumption and insufficient heat dissipation. Field emission cathodes in contrast can be operated at room temperature and with low energy consumption and are therefore well suited to be used in mobile and stationary microelectronic devices. In the process of field electron emission, electrons are promoted from a bulk material into vacuum by the action of a strong electric field in the order of 30 MV/cm. In order to created such intense electric fields one has to make use of the field enhancing effect of tip-like structures. In this context carbon nanotubes with their length of several mm and radii down to 0.7 nm represent ideal, relatively easy to make field-enhancing structures. Our goal is to realize patterned CNT thin film emitters giving 1 A/cm2 emission current density at an applied electric field below 0.1 MV/cm with an emitter density in the order of 106 cm-2. For comparison today in the same field range emission currents in the order of 10 mA/cm-2 can be obtained from as grown CNT films.