Elnobi Sahar, Sharma Subash, Araby Mona Ibrahim, Paudel Balaram, Kalita Golap, Mohd Yusop Mohd Zamri, Ayhan Muhammed Emre, Tanemura Masaki
Department of Physical Science and Engineering, Graduate School of Engineering, Nagoya Institute of Technology Gokiso-cho, Showa-ku Nagoya 466-8555 Japan
Department of Physics, Faculty of Science, South Valley University Qena 83523 Egypt
RSC Adv. 2020 Jan 3;10(2):914-922. doi: 10.1039/c9ra09038j. eCollection 2020 Jan 2.
Graphitized carbon including graphene has recently become one of the most investigated advanced materials for future device applications, but a prerequisite for broadening its range of applications is to lower its growth temperature. Here we report a great decrease in graphitization temperature using the well-known catalyst Ni. Amorphous carbon films with Ni nanoparticles (NPs) were deposited, using a simple one-step magnetron sputtering method, onto microgrids and a SiO/Si substrate for transmission electron microscopy (TEM) and Raman spectroscopy analyses, respectively. The amorphous carbon surroundings and locations between the Ni NPs started to become graphitized during the film deposition even at room temperature (RT) and 50 °C. The graphitization was confirmed by both high-resolution TEM (HR-TEM) and Raman 2D peak analyses. The increase in the relative amount of Ni in the amorphous carbon film led to the partial oxidation of the larger Ni NPs, resulting in less graphitization even at an elevated deposition temperature. Based on the detailed HR-TEM analyses, a decreased oxidation of NPs and enhanced solubility of carbon into Ni NPs were believed to be key for achieving low-temperature graphitization.
包括石墨烯在内的石墨化碳最近已成为未来器件应用中研究最多的先进材料之一，但拓宽其应用范围的一个先决条件是降低其生长温度。在此，我们报道了使用著名的催化剂镍使石墨化温度大幅降低的情况。采用简单的一步磁控溅射法，分别在用于透射电子显微镜（TEM）分析的微栅和用于拉曼光谱分析的SiO/Si衬底上沉积了含有镍纳米颗粒（NPs）的非晶碳膜。即使在室温（RT）和50°C下，在膜沉积过程中，镍纳米颗粒周围的非晶碳环境及其之间的位置也开始石墨化。通过高分辨率透射电子显微镜（HR-TEM）和拉曼二维峰分析均证实了石墨化现象。非晶碳膜中镍相对含量的增加导致较大镍纳米颗粒的部分氧化，即使在升高的沉积温度下，石墨化程度也较低。基于详细的高分辨率透射电子显微镜分析，纳米颗粒氧化的减少和碳在镍纳米颗粒中溶解度的提高被认为是实现低温石墨化的关键。
