基于电极界面调控提高OTFT注入效应的研究

发布时间：2018-03-29 16:29

本文选题：有机薄膜晶体管　切入点：酞菁铜　出处：《燕山大学》2016年硕士论文

【摘要】：有机薄膜晶体管(OTFT)具有材料来源广泛、可用于柔性衬底和大规模生产以及生产工艺简单等优点,在有机逻辑功能电路、OLED显示技术等领域有很大的发展潜力。在影响OTFT器件性能的诸多因素中,金属—半导体界面接触质量是一个非常重要的方面。实际上,由于电极与半导体能级不匹配,大部分金属—半导体的接触都为肖特基接触。因此,本文基于调控电极界面功函数的方法来进行提高薄膜器件注入效应的研究。首先,本文通过金属电极材料与酞菁铜组成金属—半导体接触界面,并分析此接触界面的能级结构和内建电场,探究金属功函数对接触电阻的影响。分析不同电极材料对OTFT接触电阻的影响,探究金属功函数对OTFT器件性能的影响。采用MoO_3修饰金属电极的方法,提高酞菁铜HOMO能级,从而降低金属—半导体界面的接触势垒,从而提高OTFT器件的载流子迁移率。其次,通过对MoO_3电极修饰层的厚度进行优化实验,得到其器件性能最佳优化厚度。通过多次实验对比三组不同MoO_3修饰层厚度(0nm,4nm,8nm)的输出特性曲线,可知4nm插入层比8nm插入层对OTFT器件性能的提升更为明显。通过分析可知,MoO_3虽然可以降低接触界面的肖特基势垒,但是MoO_3为绝缘体,过大的厚度相当于一连串的电阻串联,反而影响载流子的传输。再次,通过采用非对称电极的方法,提高OTFT器件的电流开关比。采用非对称电极(源极和漏极采用不同金属材料)结构,使电极与酞菁铜之间接触势垒提高,从而提高电极与酞菁铜接触界面的接触电阻,降低OTFT器件的关态电流。而当器件处于开态时,在一定的栅压作用下,沟道内载流子数目急剧增多,此时由非对称电极产生的接触势垒对器件的开态电流影响变的很小,因此OTFT开关比得到提高。最后,在实验室条件下,以酞菁铜为半导体材料,不同的电极组合制备了三种非对称电极结构的OTFT(Ni-Ag、Ag-Ni、Ni-Ni)。并分别对它们的接触电阻,源漏电流,输出特性曲线和转移特性曲线进行测量和分析,得到非对称电极结构对提高载流子迁移率和器件开关比有明显作用。
[Abstract]:Organic thin film transistor (OTFT) has wide material source, can be used for flexible substrate and large scale production and the production process is simple, the organic logic function circuit, OLED display technology and other fields have great potential for development. In many factors that affect the performance of the OTFT devices, metal semiconductor contact quality is a very important. In fact, the electrode and the semiconductor level does not match, the majority of metal semiconductor contact for Schottky contact. Therefore, this method is based on the regulation of the electrode interface function to improve the injection effect of thin film devices. Firstly, this paper through the metal electrode and the copper phthalocyanine is composed of metal semiconductor contact interface, and analysis build up field level structure and the contact interface, explore the impact of metal work function on contact resistance. The analysis of different electrode materials on the OTFT. Influence of contact resistance, impact on the work function of metal on the performance of OTFT. By using the method of metal modified MoO_3 electrode, improve copper phthalocyanine HOMO level, so as to reduce the contact barrier metal semiconductor interface, so as to improve the carrier mobility of OTFT devices. Secondly, optimize the experiment based on MoO_3 modified electrode layer thickness obtained the device performance optimum thickness. Through experiments comparing three different groups of MoO_3 modified layer thickness (0nm, 4nm, 8nm) the output characteristic curve, the 4nm insertion layer than 8nm into the enhance layer on the performance of OTFT is more obvious. Through the analysis, although MoO_3 Schottky barrier can reduce the contact interface, but MoO_3 an excessive thickness is equivalent to a series resistor in series, but the impact of carrier transport. Thirdly, by using the method of asymmetric electrodes, improve the current OTFT device drive Close ratio. Using asymmetric electrodes (source and drain by using different metal materials) structure, make the contact barrier increase between the electrode and the copper phthalocyanine, so as to improve the contact resistance of the electrode and the copper phthalocyanine contact interface, reduce the off state current in the OTFT device. When the device is in the open state, in effect the gate voltage next, the channel number of carrier increases sharply, the asymmetric electrode contact barrier on the device on state current effect is very small, so the OTFT switch ratio is improved. Finally, under laboratory conditions, the copper phthalocyanine semiconductor materials, different electrode preparation of three asymmetric electrode the structure of OTFT (Ni-Ag, Ag-Ni, Ni-Ni). And the contact resistance of them respectively, the source drain current, output characteristics and transfer characteristic curves were measured and analyzed by asymmetric electrode structure to improve carrier mobility and switching ratio It has an obvious effect.

【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN321.5

【相似文献】