Growth mechanism of vertically aligned SnSe nanosheets via physical vapour deposition
Growth mechanism of vertically aligned SnSe nanosheets via physical vapour deposition
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DOI：
10.1039/c4ce00213j
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发表时间：
2014-01-01
期刊：
影响因子：
3.1
通讯作者：
Sung, Yun-Mo
中科院分区：
文献类型：
--
作者：
Ma, Xing-Hua;Cho, Ki-Hyun;Sung, Yun-Mo
首次采用非催化气相合成法在不同衬底(硅、石英和氟掺杂氧化锡玻璃)上成功地合成了垂直排列的SnSe纳米片。这种与衬底无关的特性有利于各种纳米器件的制备和应用，因为它的比表面积显著增加。SnSe纳米片的厚度接近20-30 nm，横向尺寸为几个微米。X-射线衍射仪和高分辨电子显微镜的分析表明，所制备的纳米片为单晶，具有Pnma62空间群的正交晶体结构。由于SnSe晶体的各向异性原子键性质，形成了二维纳米薄片，这与定向附着生长或裸露平面抑制生长明显不同。他们还揭示了多面边缘平面，这是基于每个原子平面的表面能量的差异而详细阐明的。SnSe纳米片的直接带隙接近1.1 eV，理想地满足了作为太阳能电池应用的高性能光吸收材料的要求。
Vertically aligned SnSe nanosheets were successfully synthesized on different substrates (silicon, quartz, and fluorine-doped tin oxide glass) via a non-catalytic vapour phase synthesis method for the first time. Such substrate independent feature could benefit the fabrication and application of various nanodevices due to the considerably enhanced surface area. The SnSe nanosheets have the thickness of similar to 20-30 nm and the lateral dimension of several micrometers. The analyses using X-ray diffraction and high-resolution transmission electron microscopy demonstrate that the nanosheets are single crystalline with an ortho-rhombic crystal structure of the Pnma 62 space group. Two-dimensional nanosheets were formed due to the anisotropic atomic bonding nature of the SnSe crystal, which is apparently different from the oriented attachment growth or the exposed plane suppressing growth. They also revealed faceted edge planes, which was elucidated in detail based upon the difference in the surface energy of each atomic plane. SnSe nanosheets show a direct band gap of similar to 1.1 eV, ideally meeting the requirements as high-performance light absorbing materials for solar cell applications.