Z. D. Pesic

Low-energy electron transmission through high aspect ratio Al2O3 nanocapillaries

Electron transmission through insulating Al2O3 nanocapillaries of different diameters (40 and 270 nm) and 15 mu m length has been investigated for low-energy electrons (2-120 eV). The total intensity of transmitted current weakly depends on the incident electron energy and tilt angle defined with respect to the capillary axis. On the other hand, the intensity of elastically transmitted electrons significantly varies with the alteration of electron energy and tilt angle. In addition, we measured an energy distribution of electrons transmitted both in the straightforward direction and at large tilt angle. The measured spectra show that inelastic processes dominate and, in particular, a large amount of low-energy electrons. These low-energy electrons can be either inelastically scattered projectiles or secondary electrons emitted within the capillaries. Furthermore, a change of the tilt angle appears to influence significantly only the intensity of the elastic transmission. The present results suggest a more complex nature of low-energy electron transport through insulating nanocapillaries than proposed for positive ions. Copyright (C) EPLA, 2009

Guiding of low-energy electrons by highly ordered Al{sub 2}O{sub 3} nanocapillaries

We report an experimental study of guided transmission of low-energy (200-350 eV) electrons through highly ordered Al2O3 nanocapillaries with large aspect ratio (140 nm diameter and 15 mu 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 degrees. 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.