转角石墨烯的制备表征和应用

发布时间：2018-06-06 06:13

本文选题：石墨烯转移 + 转角双层石墨烯　；参考：《南开大学》2015年博士论文

【摘要】：当前对石墨烯研究的焦点已经从石墨烯本身的性能研究转向石墨烯先进电子器件以及石墨烯应用。石墨烯生长、加工和转移技术对于石墨烯电子器件的制备至关重要。在本论文中,我们对化学气相沉积石墨烯转移技术进行了系统的研究,对比了聚甲基丙烯酸甲酯、聚二甲基硅氧烷以及热释放胶带三种石墨烯转移方法的优缺点,发展出一种基于聚对苯二甲酸乙二醇酯/硅橡胶的新型石墨烯转移技术。硅橡胶作为吸附层,与石墨烯之间通过范德瓦尔斯力相结合,不会对石墨烯表面造成污染;聚对苯二甲酸乙二醇酯作为支撑层,有利于转移超大面积的石墨烯。这种新型转移技术具有转移品质好、转移面积大、转移效率高、可重复利用、适用范围广等优点,能够同时满足实验室和工业生产的需要。同时,我们也对具有最好品质的机械剥离石墨烯做了研究。机械剥离石墨烯在可利用的石墨烯周围存在大量杂乱无章的石墨烯碎片,这些石墨烯碎片给石墨烯杂化器件和异质结的制备带来很大困难,同时严重阻碍了石墨烯器件向集成化方向发展。因此发展一种能够将目标石墨烯单独进行转移的选择性转移技术尤为重要。在本论文中,我们发展了一种利用正性光刻胶和聚甲基丙烯酸甲酯对石墨烯进行选择性转移的新技术:利用正性光刻胶将目标石墨烯与周围碎片分隔开,利用聚甲基丙烯酸甲酯将目标石墨烯带离原基底,结合选择性转移技术,将目标石墨烯转移到任意指定位置。另外,这种新型转移技术结合了飞秒激光加工技术,对石墨烯进行图形化加工,然后将图形化的石墨烯完好地转移到新基底。利用飞秒激光加工石墨烯图形可以避免传统加工方法带来的污染问题,而且加工过程更加简单灵活。转角石墨烯的电学和光学性质区别于普通石墨烯,可以通过改变层与层之间的旋转角度进行调控。现有转角双层石墨烯制备方法主要有:(1)碳化硅外延生长,(2)折叠机械剥离石墨烯,(3)化学气相沉积生长,(4)堆叠单层石墨烯。利用这些方法制备的转角双层石墨烯旋转角度都是随机的,不具有对旋转角度进行控制的能力。利用现有方法很难制备出具有两个旋转角度的双转角三层石墨烯样品。本论文中,我们发展了一种能够对旋转角度进行精准控制的转角多层石墨烯制备技术,通过对大面积单晶单层机械剥离石墨烯的“切割”-“旋转”-“堆叠”,完成转角双层和三层石墨烯的制备。我们通过引入两条相互平行的“人造晶向”来对旋转角度进行控制,利用这种方法制备的转角石墨烯旋转角度与设计角度之间的偏差小于0.1°,这是其它制备方法所难以达到的。同时,利用这种方法制备的转角双层石墨烯具有非常高的品质。利用这种新型制备技术,我们第一次制备出具有任意角度的双转角三层石墨烯,并对它的拉曼光谱进行研究。实验结果表明,双转角三层石墨烯的拉曼光谱可以视为两个具有相应旋转角度的转角双层石墨烯拉曼光谱的叠加。这与之前关于双转角三层石墨烯电子能带结构、态密度以及光导率的理论研究相一致,证明了关于双转角三层石墨烯理论的正确性。我们对转角双层石墨烯的应用进行了探索。利用全内反射条件下石墨烯光学吸收增强,对全内反射条件下转角双层石墨烯的光电响应进行研究。实验结果表明,在全内反射条件下石墨烯光电响应具有很强的偏振依赖特性,光电流大小与激光功率成正比。在相应激光激发下,转角双层石墨烯光电流有明显增强。转角双层石墨烯的光学吸收和光电响应可以通过调节旋转角度实现有效增强。
[Abstract]:The current focus of the study of graphene has shifted from the properties of graphene itself to the advanced electronic devices of graphene and the application of graphene. The growth of graphene, processing and transfer techniques are important for the preparation of graphene electronic devices. In this paper, we have systematically studied the technology of chemical vapor deposition of graphene transfer. After comparing the advantages and disadvantages of three kinds of graphene transfer methods, polymethylmethacrylate, polymethylsiloxane and heat release tape, a new type of graphene transfer technology based on polybutylene terephthalate / silicone rubber was developed. Silicone rubber was used as an adsorption layer and the Van Der Waals force was combined with graphene by Van Der Waals force. The surface of graphene is contaminated, and polybutylene terephthalate is used as a supporting layer to transfer the large area of graphene. This new transfer technique has the advantages of good transfer quality, large transfer area, high transfer efficiency, wide application and wide application. At the same time, we can meet the needs of laboratory and industrial production. At the same time, we can meet the needs of laboratory and industrial production. Mechanical peeling graphene with the best quality has also been studied. A large number of disordered graphene fragments exist around the available graphene with mechanical peeling graphene. These graphene fragments are difficult to prepare graphene hybrid devices and heterostructures. At the same time, severe gravity hinders the integration of graphene devices into the integrated direction. Therefore, the development of a selective transfer technique that can transfer the target graphene alone is particularly important. In this paper, we developed a new technique for selective transfer of graphene by positive photoresist and polymethyl methacrylate: the use of positive photoresist to separate the target graphene from the surrounding debris. The target graphene is removed from the original substrate by using polymethyl methacrylate, and the target graphene is transferred to any specified position by the selective transfer technique. In addition, this new transfer technique combines the femtosecond laser processing technology to graphically process graphene, and then transfer graphene to a new substrate. Femtosecond laser processing graphene graphics can avoid the pollution problems caused by traditional processing methods, and the processing process is more simple and flexible. The electrical and optical properties of the angle graphene are different from the ordinary graphene, and can be regulated by changing the rotation angle between the layers and the layers. The main methods of preparing the double decker graphene are as follows: (1) The growth of silicon carbide, (2) folding mechanically stripped graphene, (3) chemical vapor deposition, and (4) stacked monolayer graphene. The rotation angle of the angular double-layer graphene prepared by these methods is random and does not have the ability to control the rotation angle. It is difficult to produce a double angle with two angles of rotation by the existing method. Three layers of graphene samples. In this paper, we developed a technique for the preparation of angular multilayered graphene, which can accurately control the angle of rotation. By "cutting" - "spin" - "stacking" of the large area single crystal single layer mechanically stripped graphene, we complete the preparation of the double layer and three layers of graphene. We have introduced two phases. The rotation angle is controlled by the parallel "artificial crystal direction". The deviation between the rotation angle and the design angle made by this method is less than 0.1 degrees, which is difficult to achieve by other preparation methods. At the same time, the angle double-layer stone with this method is very high quality. The preparation technique is the first preparation of three layers of graphene with an arbitrary angle, and its Raman spectrum is studied. The experimental results show that the Raman spectra of the double angle three layers of graphene can be regarded as the superposition of two double decked graphene spectra with corresponding angle of rotation. This is related to the previous three layers of the double angle. The theoretical study of the electron energy band structure, density of States and the optical conductivity of graphene proves the correctness of the theory about the double angle three layer graphene. We have explored the application of the double decker graphene. The experimental results show that the photoresponse of graphene has a strong polarization dependence under all internal reflection, and the size of the photocurrent is proportional to the laser power. Under the corresponding laser excitation, the optical current of the double layered graphene is obviously enhanced. The optical absorption and photoelectric response of the double decker graphene can be adjusted by adjustment. The rotation angle is effectively enhanced.
【学位授予单位】：南开大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TQ127.11

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