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Chemistry Letters Vol.34, No.7 (2005)
A Facile Route to Fabricate Single-crystalline Antimony Nanotube Arrays
Liang Li,ꢀ Yanhe Xiao, Youwen Yang, Xiaohu Huang, Guanghai Li, and Lide Zhang
Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Science,
Hefei 230031, P. R. China
(Received March 22, 2005; CL-050381)
Single-crystalline antimony nanotube arrays are fabricated
Sputter Au
in the anodic alumina membranes using the pulsed electrodepo-
sition technique for the first time. The thickness of Au layer sput-
tered on the anodic alumina membrane and the pulsed electrode-
position technique are two key factors to produce single-crystal-
line nanotubes.
Empty AAM
Electrodeposit
Sb nanotubes
Since the discovery of carbon nanotubes, much attention has
been focused on nanotube materials because of their novel prop-
erties and potential applications in nanodevices.1,2 In the recent
years, many methods have been developed to prepare different
types of nanotubes. Among these, the anodic alumina membrane
(AAM)-assisted preparation has been widely used to obtain the
desired nanotubular materials owing to their controllable sizes
and lengths of nanochannels in the AAM. However, all current
methods used the so-called ‘‘molecular anchor’’ to pretreat the
nanochannels, and the as-prepared samples were amorphous or
polycrystalline.3–5 Therefore, it is still a challenge to develop a
method to fabricate single-crystalline nanotube arrays in the
AAM by a simple route. As in bismuth, antimony (Sb) is a semi-
metal with an energy overlap (180 meV) between the conduction
and valence bands at 4.2 K, and electronic transport phenomena
occur via both electrons and holes, thus unusual transport prop-
erties can be expected in one-dimensional nanostructures of an-
timony. Sb is also a promising thermoelectric material in the fu-
ture nanodevices.6 Amorphous and polycrystalline Sb nanowires
were prepared in AAM using the vapor-phase deposition tech-
nique.6,7 Recently, our group has successfully fabricated sin-
gle-crystalline Sb nanowire arrays in AAM using pulsed electro-
deposition technique.8 However, there are few reports on the Sb
nanotubes9,10 and still no report on the fabrication of single-crys-
talline Sb nanotube arrays in AAM. In this letter, we present the
fabrication of single-crystalline Sb nanotube arrays in AAM us-
ing a pulsed electrodeposition technique for the first time.
The ordered porous AAM was prepared using a two-step an-
odic anodization process.11 A layer of Au was sputtered onto one
side of the AAM to serve as a cathode electrode. The pulsed
electrochemical deposition was carried out at ꢁ1:3 V in a com-
mon two-electrode plating cell with a graphite rod as the counter
electrode. The pulse time was 1 ms and the delayed time between
the two pulses was 2 ms. During the negative pulse time, the Sb
was electrodeposited into the pores of AAM. The electrodeposi-
tion process paused during the delayed time. The electrolyte
Dissolve
Au
and
AAM
Figure 1. Schematic representation of the fabrication of Sb
nanotube array in AAM.
80000
(1120)
60000
40000
20000
(3030)
0
20
30
40
50
2θ/degree
60
70
80
Figure 2. XRD pattern of the Sb nanotube arrays.
whose intensity is much higher than all other peaks, indicating
that the Sb nanotube arrays are highly oriented along the
ꢀ
½1120ꢂ crystal direction.
Figure 3 shows the field-emission scanning electron micros-
copy (FE-SEM, JEOL JSM-6700F) image of the Sb nanotube
array after the AAM was partly etched in 1 M NaOH solution
for 15 min, which indicates that large-area and ordered nanotube
array was formed in the AAM. From the top image of the nano-
tubes, one can see that the diameter of the nanotubes is about
60 nm, corresponding to the pore size of the AAM used.
Figure 4 shows the typical high-resolution transmission electron
microscopy (HRTEM) image of the nanotubes and correspond-
ing electron diffraction (ED) pattern (HRTEM, JEOL-2010),
which indicates that the nanotube is uniform in diameter, and
the wall thickness is about 13 nm, which is in the size range cal-
culated from the full width at half-maximum of the XRD peaks
(10–15 nm). The HRTEM lattice fringes are perpendicular to the
axis of the nanotubes and show an interplanar spacing of about
.
contained 0.01 M SbCl3, 0.06 M C6H8O7 H2O, and 0.03 M
.
Na3C6H5O7 H2O. The pH of the solution was adjusted to 2 by
adding 1 M H2SO4. A schematic representation of forming Sb
nanotube arrays is shown in Figure 1.
Figure 2 shows the X-ray diffraction (XRD, Philips PW
1700x) pattern of Sb nanotube arrays. From the pattern, we
can see that there is almost one diffraction peak of (110) plane,
ꢀ
0.213 nm, which corresponds to the ð1120Þ plane of the bulk hex-
Copyright ꢀ 2005 The Chemical Society of Japan