| In electron-beam lithography, the brightness, energy spread and shot noise of the electron source are critical in determining the resolution and throughput. Carbon nanotubes, nanometer-diameter tubes of rolled graphite layers, have demonstrated brightness values of about an order of magnitude better than traditional electron sources with similar values of energy spread. Shot noise is due to the random emission of electrons from the source. In order to reduce shot noise, electron emission must be controlled in time. The ultimate goal would be to have a turnstile electron emitter. One way to gain control is to isolate an electron in a quantum dot, and stimulate its emission by an external agent. Here the challenge is to have a quantum dot small enough to be sensitive to single electrons at room temperature. In this dissertation, it is demonstrated that a carbon nanotube cross structure can provide a solution, and our progress toward the fabrication of such a structure is described. Experiments where electron emission from the tip of a single-walled carbon nanotube is stimulated by another electron beam (with an electron multiplication factor of up to 100) are also presented. A model based on ab initio calculations is also created to explain this type of interaction. This phenomenon shows that carbon nanotubes can be used not only as controllable emitters, but also as localized (nanometer scale) electron detectors. |
