石墨烯与GaN材料的接触研究

发布时间：2018-08-24 19:46

【摘要】：石墨烯具有优异的光学、电学、机械等特性,被视为新型材料的突破口;GaN基材料具有直接宽禁带、热稳定性强、高功率等性质,已经成为“继硅之后最重要的半导体材料”。如何将石墨烯与GaN基宽禁带半导体材料相结合,发挥两种材料体系的优势,将为光电子、微电子器件的发展带来新的契机。目前,关于石墨烯与GaN基材料相结合的研究处于起步阶段,虽然已有报道利用石墨烯做电极来提高GaN基LED的发光效率,但是,在石墨烯与GaN相结合方面,仍存在诸多需要解决的问题,例如目前,通常利用转移的方式,将生长在Cu衬底上的石墨烯转移到GaN基材料上,操作困难且石墨烯的尺寸与转移位置精度难以控制,如何实现操作简单、精度可控的石墨烯与GaN接触尚有待解决。此外,如何实现石墨烯与GaN材料形成不同的接触类型,即如何形成Graphene/GaN肖特基接触,如何形成Graphene/GaN欧姆接触,其内在控制机理尚没有被阐明。本论文以“石墨烯与GaN基材料的接触”为主要研究内容,重点研究了石墨烯与GaN基材料之间的接触行为,获得了操作简单、重复性好的石墨烯/GaN形成良好接触的工艺方法,阐明了影响石墨烯/GaN接触类型的物理机理,并在此基础上,成功研制了石墨烯/GaN紫外-近红外双色探测器,为石墨烯/GaN基材料相结合的光电子器件和微电子器件的进一步发展和应用奠定了基础。本课题主要研究的内容如下:1)石墨烯与GaN材料的接触工艺研究,重点研究如何实现工艺简单、石墨烯尺寸可控、重复性高的石墨烯/GaN接触;2)石墨烯与GaN材料接触的物理机理研究,重点研究影响石墨烯/GaN接触类型的机理,研究形成欧姆或肖特基接触的条件;3)石墨烯与GaN接触的光学、电学性能的研究,并成功研制石墨烯/GaN紫外-近红外探测器本论文的创新点如下:1)首次成功利用液态石墨烯实现石墨烯与GaN基材料的接触,通过滴定法和旋涂法将石墨烯覆盖在GaN表面,形成良好的石墨烯/GaN接触。与传统的通过转移生长在Cu衬底上的石墨烯相比,本方法工艺简单、重复性高、可控性好。2)成功研制石墨烯/GaN紫外-近红外双色探测器,响应波长分别为350nm和800nm和870nm,研究了石墨烯褶皱的数量差异以及边缘形状的不同对接触行为的影响,发现,石墨烯的褶皱和石墨烯边缘形状可以调节石墨烯/GaN接触后的电学性质,石墨烯的褶皱可以作为石墨烯片状结构之间的导电通道,改善液态石墨烯层间导电性差的缺点。此外,石墨烯褶皱的形状影响石墨烯/GaN接触后GaN空间电荷区的宽度,提高肖特基势垒高度,进而提高石墨烯/GaN探测器的光响应特性。
[Abstract]:Because of its excellent optical, electrical and mechanical properties, graphene has been regarded as the breakthrough material of new material, GaN-based material with direct wide band gap, strong thermal stability, high power and so on, and has become the most important semiconductor material after silicon. How to combine graphene with wide band gap semiconductor materials based on GaN will bring a new opportunity for the development of optoelectronic and microelectronic devices. At present, the research on the combination of graphene and GaN is still in its infancy. Although it has been reported that graphene is used as electrode to improve the luminescence efficiency of GaN based LED, the combination of graphene and GaN has been reported. There are still many problems to be solved, for example, at present, graphene grown on Cu substrate is transferred to GaN substrate by transfer method, which is difficult to operate and the accuracy of the size and transfer position of graphene is difficult to control. How to realize the contact between graphene and GaN with simple operation and controllable precision remains to be solved. In addition, how to form different contact types between graphene and GaN, that is, how to form Graphene/GaN Schottky contact and how to form Graphene/GaN ohmic contact, has not been elucidated. In this paper, the contact behavior between graphene and GaN based materials is studied as the main research content, and the process of forming good contact between graphene / gan with simple operation and good repeatability is obtained. The physical mechanism influencing the type of graphene / gan contact is expounded. On the basis of this, the graphene / gan / gan UV / near infrared dual-color detector is successfully developed. It lays a foundation for the further development and application of graphene / gan based optoelectronic devices and microelectronic devices. The main contents of this subject are as follows: (1) the contact technology between graphene and GaN material, especially how to realize simple process and controllable size of graphene, The physical mechanism of graphene / gan contact with GaN materials with high reproducibility is studied. The mechanism that affects the type of graphene / gan contact is studied, and the conditions for forming ohmic or Schottky contact are studied. The optical contact between graphene and GaN is studied. Study on electrical properties and successful development of graphene / gan UV-NIR detector the innovations of this thesis are as follows: 1) the liquid graphene has been successfully used to contact graphene with GaN based materials for the first time. Graphene was coated on the surface of GaN by titration and spin-coating to form good graphene / gan contact. Compared with traditional graphene grown on Cu substrate, this method has the advantages of simple process, high repeatability and good controllability. The response wavelengths are 350nm and 800nm and 870 nm, respectively. The number difference of graphene folds and the effect of edge shape on contact behavior are studied. It is found that graphene folds and graphene edge shapes can adjust the electrical properties of graphene / gan contact. The folding of graphene can be used as a conductive channel between graphene sheet structures and improve the poor electrical conductivity between liquid graphene layers. In addition, the shape of graphene folds affects the width of GaN space charge region after graphene / gan contact, increases the Schottky barrier height, and improves the photoresponse of graphene / gan detectors.
【学位授予单位】：中国科学院研究生院(长春光学精密机械与物理研究所)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O613.71;TQ133.51

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