Growth of rectangular hollow tube crystals with rutile-type structure in supercritical fluids
Growth of rectangular hollow tube crystals with rutile-type structure in supercritical fluids
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DOI：
10.1088/1742-6596/500/2/022007
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发表时间：
2014-05
期刊：
影响因子：
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通讯作者：
K. Niwa;H. Ikegaya;T. Taguchi;S. Muto;T. Tokunaga;M. Hasegawa
中科院分区：
文献类型：
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作者：
K. Niwa;H. Ikegaya;T. Taguchi;S. Muto;T. Tokunaga;M. Hasegawa
超临界流体因其具有极高的溶解度和反应活性而被公认为是溶解和萃取过程的合适溶剂。然而，超临界流体的进一步实验发展将为材料科学，特别是新材料的合成和晶体生长提供新的视角。本文报道了在超临界流体(水或氧气)中，利用激光加热的金刚石压腔，在高达7 Gpa的压力下，成功地生长了金红石型结构的单晶(二氧化钛、共掺杂二氧化钛、二氧化硅、二氧化锗和二氧化锡)。所得产物为矩形中空管，长度为几十微米，壁厚小于500 nm。透射电子显微镜分析表明，这种矩形中空管单晶被{110}面包围，并沿[001]方向生长。{110}晶面的择优生长与金红石型结构的{110}晶面的最低表面能一致。此外，LHDAC的快速冷却速度和超临界流体的高溶解度也对矩形中空管的形成起到了重要作用。本文详细介绍了该材料的合成工艺、表征方法和生长机理。
Super critical fluids are well known as suitable solvents for dissolution and extraction processes, because it exhibits extreme high solubility and reactivity. However further experimental development using supercritical fluid would offer new insight in material science, especially the synthesis and crystal growth of novel materials. We report the successful growth of single crystals with the rutile-type structure (TiO2, Co-doped TiO2, SiO2, GeO2 and SnO2) in supercritical fluids (water or oxygen) using a laser heated diamond-anvil cell up to a pressure of 7 GPa. The resultant product showed the rectangular hollow tube morphology, a several tens of microns in length and a wall thickness of less than 500 nm. TEM analyses demonstrated that this rectangular hollow tube single crystals were surrounded by the {110} faces and grown along the [001] direction. The preferential growth of {110} faces is consistent with the lowest surface energy of {110} faces of the rutile-type structure. In addition, the rapid cooling rate in LHDAC and high solubility of supercritical fluids also play an important role for the formation of the rectangular hollow tube. The details of the synthesis procedure, characterization and growth mechanism are discussed in this paper.