化学气相沉积石墨烯薄膜的洁净转移

石墨烯因其优异的性能在很多领域具有广阔的应用前景.目前石墨烯薄膜主要是以铜作为催化基底,通过化学气相沉积法制备.这种方法制备的石墨烯薄膜需要被转移到目标基底上进行后续应用,而转移过程则会对石墨烯造成污染,进而影响石墨烯的性质及器件的性能.如何减少或避免污染,实现石墨烯的洁净转移,是石墨烯薄膜转移技术研究的重要课题,也是本综述的主题.本综述首先简单介绍了石墨烯的转移方法;进而重点讨论由于转移而引入的各种污染物及其对石墨烯性质的影响,以及如何抑制污染物的引入或如何将其有效地去除;最后总结了石墨烯洁净转移所存在的挑战,展望了未来的研究方向和机遇.本综述不仅有助于石墨烯薄膜转移技术的研究,对整个二维材料器件的洁净制备也将有重要参考价值.

Clean transfer of chemical vapor deposition graphene film

Graphene is believed to have promising applications in many fields because of its unique properties. At present, graphene films are mainly prepared on Cu substrates by chemical vapor deposition. The graphene films prepared in this way need to be transferred to the target substrates for further applications, while the transfer process inevitably induces contamination on graphene, which affects the properties of graphene and the performance of devices. Therefore, how to reduce or avoid contamination and realize the clean transfer of graphene is an important topic for the development of graphene transfer technology, which is the major topic of this review. Here, firstly, the transfer techniques of graphene are briefly reviewed, which can be classified according to different rules. For example, it can be classified as direct transfer, with which graphene is directly stuck to the target substrate, and indirect transfer, with which graphene is indirectly transferred to the target substrate with a carrier film. According to the way of separating graphene and the growth substrate, it can also be classified as dissolving transfer, with which the substrate is dissolved by chemical etchant, and delaminating transfer, with which graphene is delaminated from the substrate. Then the origins of contamination are discussed followed with how contamination affects graphene properties. The main contaminations induced by transfer are ions from the etchant and electrolyte, undissolved metal or metal oxide particles, and organic residues from carrier films. Contaminations have a great influence on the electrical, thermal and optical properties of graphene. Then the up-to-date progress of techniques for clean transfer is reviewed, including modifying the cleaning process or using alternative etchant/electrolyte to remove or suppress metal contamination and annealing graphene or using alternative carrier films (e.g., more dissoluble materials) to remove or suppress organic residues. Finally, the challenges of clean transfer of graphene are summarized, and future research directions and opportunities are prospected. This review not only contributes to the research of graphene film transfer technology, but also has great reference value for the clean fabrication of the whole two-dimensional materials and devices.