Vinsamlegast notið þetta auðkenni þegar þið vitnið til verksins eða tengið í það: http://hdl.handle.net/1946/23744
Space-charge limited emission in vacuum microdiodes can go through transverse modulation under certain conditions. The frequency of this modulated current is in the terahertz band and it can be tuned by changing either the the gap spacing or the gap voltage of the diode. Doing the latter is the preferred mode of operation during the simulations which we did. As the power of such diode radiators would be
very small, we coupled arrays of such diodes and showed that such an array, which synchronizes itself, can give powerful enough radiation for practical usage. For the emission process, it was first assumed that electrons would be emitted with zero initial velocity, as such an assumption is readily used in most emission calculations in the room temperature range. To further the research, we assumed non-zero initial velocities for the photoemitted electrons and found that, although, not without effect, the non-zero initial velocity does not significantly reduce the power of the radiator. The spatial structure of the beams was examined as well. Finally, a code for simulation of the space-charge effects in solar cells was tested, and although at present no claims can be made about these effects, the code proved to be a very good tool which replicated results from experiments and theory alike. Further experimental research on the detection of space-charge limited currents and the associated Coulomb oscillations is needed.