Unusual secondary electron emission behavior in carbon nanotube forests

Abstract

Electron yield was measured from patterned carbon nanotube forests for a wide range of primary beam energies (400-20,000 eV). It was observed that secondary and backscattered electron emission behaviors in these forests are quite different than in bulk materials. This seems to be primarily because of the increased range of electrons due to the porous nature of the forests and dependent on their structural parameters, namely nanotube length, diameter and inter-nanotube spacing. In addition to providing insight into the electron microscopy of nanotubes, these results have interesting implications on designing novel secondary electron emitters based on the structural degrees of freedom of nanomaterials.

Simple model of bulk and surface excitation effects to inelastic scattering in low-energy electron beam irradiation of multi-walled carbon nanotubes

“…22 Inelastic scattering of low-energy electrons is also employed in the characterization and fabrication of CNTbased Field-Effect-Transistors (CNT-FETs) (Ref. [23][24][25] and stimulated field-emission devices [26][27][28][29] using SEM or EBL, as well as in the quantitative interpretation of spectroscopic data from surface-sensitive techniques, such as X-ray photoelectron spectroscopy (XPS), Auger-electron spectroscopy (AES) and reflection-electron-energy-loss spectroscopy (REELS). 30,31 Finally, inelastic scattering of low-energy electrons is also important in understanding irradiation effects by high-energy ion beams [32][33][34] or from various X-ray sources 35,36 due to the role of secondary electron cascades in the spatial distribution of energy absorption in the material.…”

Quasi first-principles Monte Carlo modeling of energy dissipation by low-energy electron beams in multi-walled carbon nanotube materials

“…1,2 Scanning electron microscopy (SEM) and electron-beam lithography (EBL) are increasingly being used for the characterization and fabrication of CNT-based field-effect-transistors [3][4][5] and stimulated field-emitters. [6][7][8][9] Since electron transport plays a fundamental role in the ultimate performance of these techniques, knowledge of the energy dissipation pattern of low-energy electron beams (0.3-30 keV) in CNT materials becomes of prime importance. Monte Carlo (MC) simulations offer a valuable tool for investigating energy-transfer phenomena in irradiated solids.…”

Carbon Nanotube Electron Sources: From Electron Beams to Energy Conversion and Optophononics

“…Analytic expressions for electron/proton inelastic scattering and energy loss in carbon nanotubes have also been reported [137]. Monte Carlo modeling has also been used to study electron trajectories and backscattering in aligned carbon nanotube arrays (CNT forests) [138,139]: we have observed that, due to their mostly empty volume, CNT forests allow for an unusually high electron penetration range. The effect of different scattering models on electron penetration and backscattering studies in nanotubes has also been investigated [140] by implementing the various models in a Monte Carlo code [141].…”