有机薄膜晶体管的界面性能研究

发布时间：2018-01-09 19:12

本文关键词：有机薄膜晶体管的界面性能研究　出处：《华东师范大学》2016年博士论文　论文类型：学位论文

【摘要】：将晶体管等电子元件制备在柔性基底上进而构筑柔性电子器件,是未来电子领域重点发展的方向之一,而基于无机晶体管的电子产品一般自身柔韧性较差,大多只能制备在刚性基底上。有机薄膜晶体管(OTFT)的出现,为解决无机晶体管的发展问题提供了可行的思路。有机薄膜晶体管以其柔性、可溶液加工、材料来源广、成本低廉等优势引起了人们的极大兴趣,弥补了无机晶体管的不足。目前,有机薄膜晶体管的迁移率已达到实际应用的水平,但是对于同一种半导体而言,文献中却报道了差异巨大的迁移率数值。比如并五苯,文献中迁移率范围从0.03-6.3 cm2 V-1s-1。差异如此巨大,其原因无非就是不同研究者的器件工艺和结构的差异所导致。有机薄膜晶体管工作过程中,电荷载流子的注入和传输决定着器件的性能。电荷的注入和输出决定于源、漏电极和有机半导体之间的界面,这也是接触电阻产生的主要地方;在半导体层和绝缘层之间界面上,导电沟道形成于界面附近的半导体层一侧,而电荷载流子就从这个沟道之间进行传输。在这个区域中的界面粗糙度、缺陷和电荷等对于载流子的传输和器件的迁移率有着非常重要的影响。有机薄膜晶体管中界面质量的好坏直接决定着该器件性能的优异与否。不论是理论研究还是器件制备工艺的改进,对于界面的优化,一直是有机薄膜晶体管研究中的重要内容。本文分别对电极和有机半导体层之间界面、绝缘层和有机半导体层之间界面进行了研究。首先,研究了电极和有机半导体层之间的界面。作为有机薄膜晶体管中的重要组成部分之一,电极对于器件的性能和电路制备有着极其重要的影响。传统的金属电极通常表现出与有机半导体较差的接触质量,尤其是在底接触结构中。开发合适的修饰金属电极的材料和方法是一个有效的提升有机薄膜晶体管性能的方法,但是也是一件非常具有挑战性的工作。针对这种情况,我们发明了一种共价键合修饰氧化石墨稀到有机薄膜晶体管金属电极表面的修饰方法。这种选择性的共价键合修饰方法可以兼容各种图案化技术,而且这种共价键联接的GO-金电极对于溶液处理过程表现出很强的牢固性。更重要的是,相比于裸金电极,这种GO-金电极对于p型和n型有机半导体都有很好的普适性,这对于p型和n型有机薄膜晶体管性能的提升有着很重要的影响。操作简便、低温、兼容各种图案化技术、耐溶液处理、对于有机半导体的普适性和高性能的有机薄膜晶体管,使得该方法在有机电子学中的应用具有广阔的前景。其次,研究了绝缘层表面自组装单分子层对于有机薄膜晶体管性能的影响。通过对有机薄膜晶体管绝缘层二氧化硅表面修饰不同密度的十八烷基三氯硅烷(OTS),研究了不同密度单分子层对有机薄膜晶体管的性能影响。结果发现OTS单分子层修饰密度越高,有机薄膜晶体管器件性能越好,修饰高密度OTS的有机薄膜晶体管迁移率比不修饰OTS的器件迁移率高接近20倍。说明OTS的修饰密度对器件性能有着极大的影响,反应出绝缘层和有机半导层界面对有机薄膜晶体管性能有着决定性的影响。此外,通过改进绝缘层表面自组装单分子层修饰方法,使器件性能得到了巨大提升。十八烷基三氯硅烷(OTS)单分子层的粗糙度对于有机薄膜晶体管的性能起着特别重要的影响,但是超平膜OTS单分子层的制备是一件具有技术挑战性的工作。在第四章中,一种简单的剥离PMMA的方法被用于去除OTS表面的残留物和颗粒聚集物,这种方法可以作为一种后处理技术制备超平OTS单分子层。使用这种简单的剥离方法,OTS的修饰可以通过常规的气相沉积方法。原子力显微镜形貌测试证明了这些单分子层表现出极其平整的表面。沉积在这种超平OTS表面的有机半导体DNTT趋向于具有较大尺寸和更少边界的二维层状生长,这有利于电荷载流子的传输。基于这种超平OTS单分子层,DNTT和PDI-8CN2有机薄膜晶体管的迁移率分别高达8.16cm2 V-1 s-1和0.30cm2 V-1 s-1,并且具有很高的重复性,这都显著优于未经揭膜处理OTS的有机薄膜晶体管性能。这项工作解决了一个关于OTS修饰质量的常见但是极其棘手的问题。其对于有机薄膜晶体管的性能提升和制备重复性具有非常重要的意义。
[Abstract]:The transistor and other electronic components prepared on flexible substrate, build a flexible electronic device, is one of the future direction of the electronic field focus on the development of electronic products, and inorganic transistors are mostly only based on its poor flexibility, prepared on the rigid substrate. The organic thin film transistor (OTFT) has provided a feasible way for the development of to solve the problem of inorganic organic thin film transistor transistor. With its flexible solution process, wide material source, low cost and other advantages has aroused great interest, to compensate for the lack of inorganic transistors. At present, the migration of organic thin film transistor has reached the level of practical application, but for the same kind of semiconductor, literature it is reported a huge difference in mobility. For example, five numerical and benzene, literature migration rate range from 0.03-6.3 cm2 to V-1s-1. such a huge difference, the reason is nothing more than Is the difference in device technology and structure of different researchers. The organic thin film transistor working process, injection and transport of charge carriers determines the performance of the device. The charge injection and the output depends on the source of leakage between the electrode and the organic semiconductor interface, which is the main place of contact resistance generated in the semiconductor layer; the interface between the insulating layer and the semiconductor layer, a conductive channel is formed on the side near the interface, and the charge carriers from between the channel for transmission. In this region the interface roughness, has very important effect on the migration rate of defects and charge for transmission devices and carriers. The interface quality of organic thin film the transistor directly determines the performance of the device is excellent or not. Both the theoretical research and fabrication process improvement, for the optimization of the interface, has been the organic film The important content in the research of this paper. The transistor on the interface between the electrode and the organic semiconductor layer of insulating layer and the interface between the organic semiconductor layer. First of all, between the electrode and the organic semiconductor layer interface. As an important part of the organic thin film transistor, electrode preparation has a great effect on the performance of and the circuit device. Conventional metal electrodes usually exhibit poor quality of contact with the organic semiconductor, especially in the bottom contact structure. Materials and methods suitable for the development of modified metal electrode is an effective method for improving the performance of organic thin film transistor, but is also a very challenging work for. In this case, we have developed a covalent modification of graphene oxide to the surface modification of organic thin film transistor metal electrode. This selective The covalent modification method can be compatible with a variety of patterning, and the GO- gold electrode connected to the covalent bond solution process showed a strong firm. More importantly, compared to the bare gold electrode, the GO- electrode has good universality for P type and N type organic semiconductor and it has a very important impact on the performance of the transistors P and N type organic thin film promotion. The operation is simple, low temperature resistance, compatible with a variety of patterning, solution treatment, for the organic semiconductor universality and high performance organic thin film transistor, the method has a broad prospect in the field of organic electronics. Secondly, influence of insulating layer on the surface of a self-assembled monolayer on the performance of organic thin film transistors were studied. Based on the organic thin film transistor insulating layer of silicon dioxide surface modified with different density of eighteen alkyl three chloro silane (O TS), study the different density of single molecular layer of the organic thin film transistor performance influence. The results showed that the OTS monolayer density is high, the performance of organic thin film transistor device better, organic thin film transistor modified high density OTS mobility than devices without modification of OTS migration rate close to 20 times. The modified density of OTS have a great effect on the performance of the device, in response to the insulating layer and the organic semiconducting layer on the performance of organic thin film transistors have a decisive impact. In addition, by improving the surface of an insulating layer of self-assembled monolayer modified method, the performance of the device has been a huge boost. Eighteen three alkyl chlorosilane (OTS) single molecule the roughness layer for organic thin film transistor performance plays a very important influence, but the ultra flat membrane OTS monolayer preparation is a technically challenging work. In the fourth chapter, a simple Method of stripping PMMA is used to remove residues and particles on the surface of OTS aggregates, this method can be used as a postprocessing technique for the preparation of ultra flat OTS single molecular layer. The use of the release in this simple way, OTS can be modified by conventional vapor deposition method. Atomic force microscope morphology test proved that the single the molecular layer showed extremely smooth surface. The deposition in this ultra flat organic semiconductor DNTT OTS surface tends to 2D growth with larger size and less boundary, which is conducive to the transmission of the charge carriers. This ultra flat OTS single molecule layer based on the migration of DNTT and PDI-8CN2 organic thin film transistor rate as high as 8.16cm2 V-1 S-1 and 0.30cm2 V-1 s-1, and has high repeatability, which is significantly better than the performance of organic thin film transistor removingfilm processing of OTS. This work solves a modified OTS The common but extremely difficult problem of quality is of great importance to the performance enhancement and reproducibility of the organic thin film transistors.

【学位授予单位】：华东师范大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN321.5

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