Bismuth quantum-wires arrays fabricated by electrodeposition in nanoporous anodic aluminum oxide and its structural properties

Abstract

Ultrafine bismuth nanowire arrays have been fabricated by electrodeposition into nanoporous anodic aluminum templates in a composite electrolyte solution, in which the diameter of nanowire as low as 3 nm can be obtained. The micrographs and crystal structures of Bi nanowires are studied by transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and X-ray diffraction (XRD). It is found that each nanowire is essentially a single crystal and has a different orientation in an array. The optical properties of the Bi nanowire arrays are studied by UV-VIS spectra. The experimental results exhibit blue-shifted phenomena with decreasing wire diameter, which is qualitatively consistent with the effective medium theory. © 2000 Elsevier Science S.A. All rights reserved.Keywords: Quantum-wires arrays; Aluminum oxide; Bismuth nanowire www.elsevier.com/locate/mseb Semimetallic bismuth is a material exhibiting interesting magnetoresistance (MR) characteristics and finitesize effects, whose electronic properties are fundamentally different from those of common metals due to the complex and highly anisotropic Fermi surface [1][2][3][4][5][6][7]. Especially, ultrafine bismuth nanowires arrays are considered a good candidate to study quantum confinement effect, which is desirable for wide-field sensing [8] [9,10,12,13]. However, the attribution of pores of polycarbonate membrane is not uniform, which can not be used to fabricate the high quality arrays of Bi nanowires. The pressure injection method or a vaporphrase technique is difficult to fabricate the pore diameter of bismuth nanowires below 10 nm. And this method is highly costly, and complex in operation. If the fabrication by electrodeposition into nanoporous anodic aluminum oxide (AAO) can be carried out, the shorts can been avoided. To the best of the authors' knowledge, the arrays of Bi nanowires were not prepared by electrodeposition into nanoporous AAO films. The possible reason is that the bismuthal salt is very easy to hydrolyze. When the solution pH is controlled under 0.9 or lower, the nanoporous AAO templates are dissolved in solution.When anodized in an acidic electrolyte, aluminum forms a porous oxide with very uniform and parallel pores open at one end and sealed at the other [15][16][17][18]. Its structure is described as a closed-packed array of columnar cells, each containing a central pore of which the side and interval can be controlled by changing the forming conditions. In recent years, there has been interest in this material as a medium for creating uniform nanostructures since its pores can function as 'nanotemplates' in which small metal and semiconductor particles can be electrochemically deposited [15][16][17][18][19][20][21][22].Here, the Bi quantum-wire arrays were electrodeposited in nanoporous AAO membranes by a novel deposition electrolyte solution which was prepared. The technique successfully carried out the fabrication of Bi * Corresponding author.0921-5107/00/$ -see front matter © 2000 Elsevier Science S.A....

Magnetic and magnetization properties of electrodeposited fcc CoPt nanowire arrays

“…Its structure is described as a closedpacked array of columnar cells, each containing a central pore of which the size and interval can be controlled by changing the forming conditions. In recent years, there has been interest in this material as a medium for creating uniform nanostructures since its pores can function as 'nanotemplates' in which small metal and semiconductor particles can be electrochemically deposited [14]. The ferromagnetic nanowires fabricated in such templates have high coercivity (H c ) and remanence with an easy axis parallel to the nanowires axis due to the dominant role of shape anisotropy in effective magnetic anisotropy, which can be minimized by increasing the diameter of the templates.…”

Co-rich cobalt platinum nanowire arrays: Effects of annealing

“…15 The electrolytes in this work consisted of 0.5 g / l PtCl 4 , 96 g / l CoSO 4 ·7H 2 O and 42 g / l H 3 BO 3 . The electrolysis was carried out at room temperature for 40 s with an ac voltage ͑frequency = 200 Hz͒ of 13 V.…”

Growth of Semimetals Bismuth and Antimony Films on Reactive Substrate

“…Bi nanowires and nanorods were prepared by high pressure injection of the liquid metal or vapor phase of bismuth into the channels of porous anodic alumina template [6,7]. Bismuth nanowires have also been electrodeposited into nanometer-sized pores of polymer [8] or nanoporous anodic alumina [9,10]. Solution chemical methods have also been explored for the synthesis of Bi nanowires and nanotubes [11][12][13].…”