Double-helical silicon microtubes.
Double-helical silicon microtubes.
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DOI：
10.1002/anie.200907271
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发表时间：
2010-05
影响因子：
--
通讯作者：
H. Morito;H. Yamane
中科院分区：
文献类型：
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作者：
H. Morito;H. Yamane
自然界中存在的各种螺旋，例如海螺壳、植物藤蔓以及我们体细胞中的DNA，其无限的螺旋几何形状令人着迷。在艺术和工业中，螺旋结构也是人工创造的。碳纳米管是最著名的螺旋结构材料，其电子行为依赖于螺旋结构。[1-3]碳和碳化硅（SiC）的螺旋线圈以及氧化锌（ZnO）的螺旋带也已经合成，并且引起了人们对螺旋形状的潜力的极大关注。[4-6]硅块体晶体和薄膜广泛用于电子器件和太阳能电池。硅的晶须、纳米线和纳米管也已经被制造出来。[7-11]然而，尚未报道硅的螺旋结构。本研究以Zintl化合物NaSi为原料，采用一种新的方法成功地合成了硅双螺旋微管。[12]合成程序的细节描述于实验部分中。在温度梯度反应器中，将压实的NaSi粉末的盘从室温加热至800 ° C持续1小时。将该温度保持12小时，并从NaSi盘蒸发Na。在加热之后，获得多晶硅盘。在圆盘表面获得大量微管（支持信息中的图S1）。表面突起的顶端生长出直径约10-50 μm的金属丝。线的长度范围从约几百微米到2.5 mm。图1显示了在样品上观察到的线的SEM图像。大多数丝具有双螺旋结构，具有各种表面形貌，
The various helices that occur in nature, for example, conch shells, vines of plants, and the DNA in our somatic cells, are fascinating with their infinite helical geometry. Helical structures are also artificially created in art and industry. Carbon nanotubes are the most famous materials with helical structures, on which the electronic behavior of the nanotubes depends.[1–3] Helical coils of carbon and silicon carbide (SiC) as well as helical belts of zinc oxide (ZnO) have also been synthesized and have attracted much attention to the potential of helical shapes.[4–6] Silicon bulk crystals and thin films are widely used for electric devices and solar batteries. Whiskers, nanowires, and nanotubes of Si have also been fabricated.[7–11] However, helical structures of silicon have not been reported. In the present study, we succeeded in synthesizing double-helical microtubes of silicon by a new method in which a Zintl compound NaSi was used as the starting material.[12]Details of the synthetic procedure are described in the Experimental Section. A disk of compacted NaSi powder was heated from room temperature to 8008C for 1h in a temperature-gradient reactor. This temperature was maintained for 12 h, and Na was evaporated from the NaSi disk. After the heating, a disk of polycrystalline Si was obtained. A large number of microtubes were obtained on the disk surface (Figure S1 in the Supporting Information). Wires of about 10–50 μm in diameter grew from the top of protuberances of the surface. The lengths of the wires ranged from about several hundred micrometers to 2.5 mm. Figure 1 shows SEM images of the wires observed on the sample. Most wires had double helical structures with various surface morphologies such