Simulation Study of Beam Temperature Effects of Carbon Nanotubes Field Emission Source

摘要

Carbon nanotubes (CNTs) are promising electron sources for field emission displays (FEDs) due to their excellent characteristics. But the temperature effects upon the spreading of the emitting electrons and upon the field emission characteristics have seldom been discussed. In this study, the particle-in-cell finite-difference time-domain (PIC-FDTD) method is used to study the temperature effects of the electron beams. A field emission model based on the Fowler-Nordheim equation using the local electric field at the nanotube top is established. The transverse and longitudinal temperature effects are introduced through adding energy of the emitted electrons with the Botlzmann distribution. For considering the junction effects of the carbon nanotubes grown on doped silicon substrate, the phenomena of the reversed saturated currents are also included in our emission model. Moreover, due to the essence of the PIC-FDTD method, the space-charge effects are considered in the simulation automatically. The simulation geometry is shown in figure 1. The two-dimensional cylindrical coordinate (z - r - v) with v symmetry is adopted.