Low-energy electron transmission through high aspect ratio Al₂O₃ nanocapillaries

¹  Laboratory for Atomic Collision Processes, Institute of Physics - Pregrevica 118, 11080 Belgrade, Serbia
²  Unité de Physico-Chimie et de Physique des Matériaux, Université Catholique de Louvain - Place Croix du Sud, 1, B-1348 Louvain-la-Neuve, Belgium, EU

Corresponding author: vraz@phy.bg.ac.yu

Received: 20 February 2009
Accepted: 25 March 2009

Abstract

Electron transmission through insulating Al₂O₃ nanocapillaries of different diameters (40 and 270 nm) and 15 μm 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.