Imaging of As- and B-doped silicon regions has been performed in a scanning electron microscope operated in the cathode lens mode, with incident electron energies (EP) as low as 15 eV. The doped regions of n+ (As, 2.5×1020 cm−3) and p+ (B, 8×1019 cm−3) on n-type silicon (∼1015 cm−3) show distinct contrast with electron energies of about 3 keV. The brightest region is n+ followed by p+, then the n-type substrate. The highest contrast for the p+ and n+ type regions is reached at about EP=300 and 15 eV, respectively. The contrast mechanisms are explained in terms of metal-semiconductor contact assuming an adventitious carbon film at the surface.

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Carbon nanotubes (CNTs) are a unique form of carbon filament/fiber in which the graphene walls roll up to form tubes. They can exhibit either metallic-like or semiconductor-like properties. With the graphene walls parallel to the filament axis, nanotubes (single wall metallic-type or multi-wall) exhibit high electrical conductivity at room temperature. This high electrical conductivity allied to their remarkable thermal stability has made CNTs one of the most intensely studied material systems for field emission (FE) applications. In this paper we will describe the growth of multiwall CNTs and their application in a range of field emission based systems including their use in SEM sources, emitters for use in microwave amplifiers and as emitters in field emission based displays (FEDs).

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