Zhang Tian-Tian, Lv Bing-Hao, Fan Chen-Chen, Shi Bi-Yun, Cao Qiao-Jun, Wang Wei, Tao Fei-Fei, Dou Wei-Dong
Laboratory of Low-dimensional Carbon Materials and Department of Physics, Shaoxing University, Shaoxing 312000, China.
School of Civil Engineering, Shaoxing University, Shaoxing 312000, China.
ACS Omega. 2023 Sep 20;8(39):36245-36252. doi: 10.1021/acsomega.3c04784. eCollection 2023 Oct 3.
As an important member of the graphene family, vertical graphene (VG) has broad applications like field emission, energy storage, and sensors owing to its fascinating physical and chemical properties. Among various fabrication methods for VG, plasma enhanced chemical vapor deposition (PECVD) is most employed because of the fast growth rate at relatively low temperature for the high-quality VG. However, to date, relations between growth manner of VG and growth parameters such as growth temperature, dosage of gaseous carbon source, and electric power to generate plasma are still less known, which in turn hinder the massive production of VG for further applications. In this study, the growth behavior of VG was studied as functions of temperature, plasma power, and gas composition (or chamber pressure). It was found that the growth behavior of VG is sensitive to the growth conditions mentioned above. Although conditions with high growth temperature, large flow rate of mixed gas of methane and carrier gases, and high plasma power may be helpful for the fast growth of VG, brunching of VG is simultaneously enhanced, which in turn decreases the vertical growth nature of VG. High-quality VG can be achieved by optimizing the growth parameters. It was revealed that the vertical growth nature of VG is governed by the electric field at the interfacial layer between VG and the substrate, for which its strength is influenced by the density of plasma. These findings are important for the general understanding of the VG growth and provided a feasible way for the controllable fabrication of VG using the remote PECVD method which is usually believed to be unsuitable for the fabrication of VG.
作为石墨烯家族的重要成员，垂直石墨烯（VG）因其迷人的物理和化学性质而在场发射、能量存储和传感器等领域具有广泛应用。在各种垂直石墨烯的制备方法中，等离子体增强化学气相沉积（PECVD）应用最为广泛，因为它能在相对较低温度下实现高质量垂直石墨烯的快速生长。然而，迄今为止，垂直石墨烯的生长方式与生长温度、气态碳源用量以及产生等离子体的电功率等生长参数之间的关系仍鲜为人知，这反过来阻碍了垂直石墨烯的大规模生产以用于进一步应用。在本研究中，研究了垂直石墨烯的生长行为与温度、等离子体功率和气体组成（或腔室压力）的函数关系。发现垂直石墨烯的生长行为对上述生长条件敏感。尽管高温、甲烷与载气混合气体的大流量以及高等离子体功率的条件可能有助于垂直石墨烯的快速生长，但垂直石墨烯的分支同时增加，这反过来降低了垂直石墨烯的垂直生长特性。通过优化生长参数可以实现高质量的垂直石墨烯。结果表明，垂直石墨烯的垂直生长特性由垂直石墨烯与衬底界面层处的电场决定，该电场强度受等离子体密度的影响。这些发现对于全面理解垂直石墨烯的生长具有重要意义，并为使用通常被认为不适用于垂直石墨烯制备的远程PECVD方法可控制备垂直石墨烯提供了一条可行途径。
