In situ gas analysis during the growth of hexagonal boron nitride from ammonia borane
In situ gas analysis during the growth of hexagonal boron nitride from ammonia borane
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DOI：
10.1088/2053-1591/aa9a7f
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发表时间：
2017-11
影响因子：
2.3
通讯作者：
G. Wood;Zachary P. L. Laker;A. J. Marsden;G. Bell;N. Wilson
中科院分区：
文献类型：
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作者：
G. Wood;Zachary P. L. Laker;A. J. Marsden;G. Bell;N. Wilson
氨硼烷 (NH3:BH3) 通常用作氮和硼的化学计量源，用于通过化学气相沉积 (CVD) 生长六方氮化硼 (h-BN)。我们使用质谱原位气体分析来研究氨硼烷源加热时释放的活性化学成分，并研究这些成分在流过 CVD 生长炉后如何变化。这也让我们深入了解用于 CVD 生长 h-BN 的铜基材的催化效果。我们发现，在真空中，即使在 40 °C 的温度下，气态氨基硼烷和聚氨基硼烷碎片也会从固体源中演化出来；随着氨硼烷源的温度升高，所有组分的量增加，但存在比例更多的较高质量组分。气相反应会改变流过 CVD 生长炉后的气体成分，具体取决于生长炉的温度，在较高的炉温下脱氢会增加。进一步的反应由铜基材催化，在炉温 $ ?>> 900 °C 时，较高质量组分的分解明显。与 CVD h-BN 生长的直接比较表明，对于较大的岛尺寸，优选通过较低的氨硼烷源温度产生的较低质量的组件，并且需要高于 900 °C 的炉温才能启动铜基材的催化作用。因此，原位气体分析为 h-BN 的 CVD 生长提供了新的见解，并且可以使用类似的方法来优化和理解其他二维材料的生长。
Ammonia borane (NH3:BH3) is commonly used as a stoichiometric source of nitrogen and boron for the growth of hexagonal boron nitride (h-BN) by chemical vapour deposition (CVD). We use in situ gas analysis by mass spectrometry to investigate the active chemical components that evolve when an ammonia borane source is heated, and study how these components change after flowing through the CVD growth furnace. This also gives insight into the catalytic effect of copper substrates used for CVD growth of h-BN. We find that in vacuum, even at 40 °C, gaseous amino borane and polyaminoborane fragments are evolved from the solid source; as the temperature of the ammonia borane source increases, the amount of all components increases but proportionally more of the higher mass components are present. Gas phase reactions change the gas composition after flowing through the CVD growth furnace, depending on the temperature of the growth furnace, with increased dehydrogenation at higher furnace temperatures. Further reactions are catalysed by the copper substrate, with decomposition of the higher mass components evident at furnace temperatures $ ?>>900 °C. Direct comparison with CVD h-BN growth suggests that the lower mass components produced by lower ammonia borane source temperatures are preferred for larger island sizes and that furnace temperatures higher than 900 °C are required in order to initiate the catalytic effects of the copper substrate. In situ gas analysis thus gives new insight into the CVD growth of h-BN, and similar methodology could be used to optimise and understand the growth of other two dimensional materials.