Simulation Study of Screen Effects on Field Emission from Multiple One-dimensional Nanostructures Grown on Silicon Substrates

Summary form only given. In our previous work, a classical carrier transport model is established to study the junction effects on the field emission currents of the narrow- and wide-band-gap single one-dimensional nanostructure grown on n-type and p-type doped silicon substrates. Our simulation results agree with the experiments qualitatively and provide a perspicuous explanation for the junction effects by using the band structure theory. But the screen effects of the multiple nanostructures on the band structures around the nanostructure-substrate interface and on the field emission currents are not clear yet. In this study, the carrier transport model mentioned above is applied to investigate the screen effects of the multiple one-dimensional nanostructures. The classical transport equation is used to describe the carrier transport in the material and solved together with the Poisson´s equation. The field emission at the emitter-vacuum interface is modeled by the Fowler-Nordheim equation. For studying the interaction between the multiple nanostructures, two nanorods with different heights and distances in the simulation domain are modeled and accompanied with a pair of periodic boundary conditions. Figure 1 presents the geometry model in this research. The CNT and SiCN 1-D nanorods are grown on n/p-type Si substrate with the doping concentration of 10¹⁵ I/cm³. Figure 2 and 3 present the electrostatic contours, the band diagrams for the side nanorods and the F-N plots for the SiCN nanorods with n-type substrate and inter-rod distances of 0.1 mum and 0.3 mum, respectively. Our simulation results exhibit that when two nanorodes are close, the screen effects will distort the electric potential distribution around the nanorods and change the band structure at the nanostructure-substrate interface. Therefore, the field emission characteristics are very different for each nanorod in the closely-aligned nanostructure arrays