Guiding of low-energy electrons by highly orderedAl2O3nanocapillaries

Abstract

We report an experimental study of guided transmission of low-energy $(200--350\phantom{\rule{0.3em}{0ex}}\mathrm{eV})$ electrons through highly ordered ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ nanocapillaries with large aspect ratio ($140\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ diameter and $15\phantom{\rule{0.3em}{0ex}}\mathrm{\ensuremath{\mu}}\mathrm{m}$ length). The nanochannel array was prepared using self-ordering phenomena during a two-step anodization process of a high-purity aluminum foil. The experimental results clearly show the existence of the guiding effect, as found for highly charged ions. The guiding of the electron beam was observed for tilt angles up to $12\ifmmode^\circ\else\textdegree\fi{}$. As seen for highly charged ions, the guiding efficiency increases with decreasing electron incident energy. The transmission efficiency appeared to be significantly lower than observed for highly charged ions and, moreover, the intensity of transmitted electrons significantly decreases with decreasing impact energy.