For more than two decades, carbon nanotubes (CNTs) have shown great potential for a wide range of applications. Several methods are known to synthesize CNTs, though only a few of them are able to produce good quality and economically available CNTs. Chemical vapor deposition (CVD) is one of those methods that produce economically feasible and good quality CNTs onto specific substrates, even with nanopatterning. However, growing CNTs by CVD at temperatures below 700 °C remained a long-time challenge, as this meant keeping a host of low-melting materials out of bounds for direct CNT growth on them. In this work, CNTs have been synthesized directly onto a low-melting, conducting substrate, aluminum, by thermal CVD, at a temperature as low as 550 °C and up to as high as 650 °C (just below the melting point of aluminum). The diameters of the grown CNTs were observed to be influenced by process parameters, e.g., temperature and pressure. The effect of synthesis parameters on CNT diameters was verified by scanning electron microscopy and transmission electron microscopy. The quality of the CNTs was checked by Raman spectroscopy, selected area electron diffraction pattern of transmission electron microscopy, and XPS. It was observed that an increase in temperature and pressure had a significant effect on the diameters of the CNTs. Randomly entangled CNTs were measured to have an average diameter of 28 nm at 550 °C and one atmospheric (760 Torr) pressure, whereas it was observed to be 78 nm at a temperature of 650 °C and pressure of 0.01 Torr. The field emission response, i.e., the turn-on field (2.5 V/μm) and the maximum emission current density (2.17 mA/cm²) of the CNTs synthesized at the temperature of 550 °C and pressure of 1 atm (760 Torr) was found to be excellent.

中文翻译：

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在铝基板上系统生长碳纳米管以增强场发射性能

二十多年来，碳纳米管（CNT）在广泛的应用中显示出巨大的潜力。已知几种合成CNT的方法，尽管只有少数方法能够生产高质量和经济上可用的CNT。化学气相沉积（CVD）是即使在进行纳米构图的情况下，也可以在特定的基材上生产经济可行的高质量CNT的方法之一。然而，在低于700°C的温度下通过CVD生长CNT仍然是一个长期的挑战，因为这意味着要使许多低熔点材料无法直接在其上进行CNT生长。在这项工作中，碳纳米管已经通过热CVD在低至550°C至最高650°C（仅低于铝的熔点）下直接合成到低熔点导电基材铝上）。观察到生长的CNT的直径受工艺参数例如温度和压力的影响。通过扫描电子显微镜和透射电子显微镜验证了合成参数对CNT直径的影响。通过拉曼光谱，透射电子显微镜的选择区域电子衍射图和XPS检查了CNT的质量。观察到温度和压力的增加对CNT的直径具有显着影响。在550℃和一个大气压（760Torr）的压力下，无规缠结的CNT的平均直径被测量为28nm，而在650℃的温度和0.01Torr的压力下被观察为78nm。场发射响应，即开启场（2.5 V / 温度和压力。通过扫描电子显微镜和透射电子显微镜验证了合成参数对CNT直径的影响。通过拉曼光谱，透射电子显微镜的选择区域电子衍射图和XPS检查了CNT的质量。观察到温度和压力的增加对CNT的直径具有显着影响。在550℃和一个大气压（760Torr）的压力下，无规缠结的CNT的平均直径被测量为28nm，而在650℃的温度和0.01Torr的压力下被观察为78nm。场发射响应，即开启场（2.5 V / 温度和压力。通过扫描电子显微镜和透射电子显微镜验证了合成参数对CNT直径的影响。通过拉曼光谱，透射电子显微镜的选择区域电子衍射图和XPS检查了CNT的质量。观察到温度和压力的增加对CNT的直径具有显着影响。在550℃和一个大气压（760Torr）的压力下，无规缠结的CNT的平均直径被测量为28nm，而在650℃的温度和0.01Torr的压力下被观察为78nm。场发射响应，即开启场（2.5 V / 通过拉曼光谱，透射电子显微镜的选择区域电子衍射图和XPS检查了CNT的质量。观察到温度和压力的增加对CNT的直径具有显着影响。在550℃和一个大气压（760Torr）的压力下，无规缠结的CNT的平均直径被测量为28nm，而在650℃的温度和0.01Torr的压力下被观察为78nm。场发射响应，即开启场（2.5 V / 通过拉曼光谱，透射电子显微镜的选择区域电子衍射图和XPS检查了CNT的质量。观察到温度和压力的增加对CNT的直径具有显着影响。在550℃和一个大气压（760Torr）的压力下，无规缠结的CNT的平均直径被测量为28nm，而在650℃的温度和0.01Torr的压力下被观察为78nm。场发射响应，即开启场（2.5 V / 在550℃和一个大气压（760Torr）的压力下，无规缠结的CNT的平均直径被测量为28nm，而在650℃的温度和0.01Torr的压力下被观察为78nm。场发射响应，即开启场（2.5 V / 在550℃和一个大气压（760Torr）的压力下，无规缠结的CNT的平均直径被测量为28nm，而在650℃的温度和0.01Torr的压力下被观察为78nm。场发射响应，即开启场（2.5 V /发现在550℃的温度和1atm的压力（760Torr）下合成的CNT的最大发射电流密度（μm）和优异的最大发射电流密度（2.17mA / cm ²）是极好的。