Guided transmission of slow Ne⁶⁺ions through the nanochannels of highly ordered anodic alumina

Abstract

A highly ordered hexagonally close-packed nanochannels array was prepared using the self-ordering phenomena during a two-step anodization process of a high purity aluminium foil. The anodized aluminium oxide, with pore diameters of about 280 nm and interpore distances of about 450 nm was prepared as a suspended membrane of about 15 µm thickness on the aluminium frame to which it belongs. The Al 2 O 3 capillaries were bombarded with 3 keV Ne 6+ ions. The first results unambiguously show the existence of ion guiding observed at 5 • and 7.5 • tilt angles of the capillaries compared to the beam direction. To the best of our knowledge, such ion guiding effects of slow ions through hexagonally ordered nanochannels in alumina has not been reported previously.

Transmission of 16keV Cu− ions through Al2O3 nano-capillaries

“…Interaction of charged ions with capillaries made from metals [2,3] and insulators [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] has been widely studied both experimentally and theoretically. For metals, it is aimed to the formation of hollow atoms via charge exchange processes under grazing incidence of HCIs at the capillary walls [2,3].…”

“…The guiding phenomenon involves the charging up of inner capillary walls, where incident ions are deflected by the charge patches sequentially formed in the entrance region [7]. Guiding effect has been found in capillaries with different sizes, aspect ratios, different materials and projectiles, in a wide energy range (e.g., 3-100 keV) [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. In these recent works, time or deposited-charge evolution related to the angular distribution of the guided ions was measured and analyzed in detail.…”

Ion guiding in alumina capillaries: MCP images of the transmitted ions

“…They might be used for irradiating single cells and writing on charge sensitive surfaces. Collecting experimental data with capillary samples made of different kinds of materials is of a great importance for the understanding of this self-organizing phenomenon [1][2][3][4][5][6][7][8][9].…”

“…The capillaries were prepared at UCL using the self-ordering phenomena during a two-step anodization process. The details of the preparation are given in [9]. We measured angular and charge state distributions of the transmitted ions with two techniques using a position sensitive MCP detector and an electrostatic spectrometer.…”

Density effects on the guided transmission of 3keV Ne7+ ions through PET nanocapillaries

“…In contrast to the work with metals [7,8], a considerable fraction of ions is guided through the capillary in its incident charge state. Due to the increasing interest in this subject, several laboratories started investigations of capillary guiding using PET [9][10][11], SiO 2 [12] and Al 2 O 3 [13][14][15]. Moreover, electrons were used as projectiles guided through capillaries in Al 2 O 3 [16] and PET [17].…”