基于非对称结构的有机半导体喷墨打印工艺及其取向机制研究

发布时间：2018-05-26 02:25

本文选题：有机薄膜晶体管 + 表面能　；参考：《合肥工业大学》2017年硕士论文

【摘要】：喷墨打印的方法由于工艺简单、成本低廉且能精确图案化等优点而备受关注。对于溶液法而言,通过工艺改进对溶液法制备的有机半导体材料的生长进行取向控制能提高制备的有机薄膜晶体管(OTFT)的性能。在众多的取向控制原理中,对表面能进行调节可以有效控制喷墨打印溶液的干燥行为,为底接触OTFTs的喷墨打印制备提供了新的改进思路。本文的主要研究为设计和构建了不同材料的不对称电极(拥有不同的表面能),对喷墨打印溶液进行诱导形成取向生长结晶,优化有机薄膜晶体管的性能。在此框架下,我们研究了具体的制备参数与方法,及其对不对称电极诱导作用的影响与微观动力学机制。主要内容如下:(1)制备了底接触金-银不对称电极器件,研究了半导体墨水在此结构器件沟道处的干燥过程及内部溶液的流动过程。半导体溶液墨水在不同材料衬底上表现出的不同接触角将打破液体/空气界面处的表面张力与表面能的总体平衡。溶液内部的表面张力存在梯度,在不对称的马兰戈尼流的作用下使得溶液从接触角较大的一侧后退,形成横跨沟道生长结晶,提升了沟道处的电荷传输性能。对实验条件如衬底温度、沟道长度、喷墨打印点间距等进行了系统的研究,分析了其对于薄膜形貌和器件性能的影响。对OTFT器件的接触电阻与体电阻进行了系统的分析,明确了控制结晶生长过程工作的意义。在最优条件下制备的OTFTs在迁移率上相对于原始器件有了近2.5倍的提升。同时多器件制备的均匀性也因为薄膜的受控生长而得到了提升。(2)采用化学气相沉积(CVD)法制备石墨烯薄膜。对石墨烯生长过程的工艺与参数进行了研究,通过对薄膜形貌与电学性能的表征,确定了较优的CH4气流量为20 sccm,H2气流量为20 sccm。通过拉曼光谱证明了在最优条件下制备的薄膜为高质量的单层石墨烯薄膜,可以用作器件电极材料。探究了不同的转移与图案化石墨烯电极的方法,通过形貌表征分析各方法的利弊,明确了采用先转移后刻蚀的方法制备底接触金-石墨烯不对称电极器件。使用喷墨打印法制备器件有源层,半导体墨水在不对称衬底的诱导作用下形成横跨沟道生长的结晶。在石墨烯与半导体材料能级不匹配的情况下,器件结晶形貌的优化仍然使得迁移率相对原始器件有了 2倍的提升。本论文提出的具有诱导取向作用的器件结构与其他提升OTFTs性能的方法在原理上有较好的兼容性,进一步研究可以尝试将不对称结构与其他方法相结合。
[Abstract]:Ink jet printing has attracted much attention due to its advantages of simple process, low cost and accurate patterning. For solution, the orientation control of organic semiconductor materials prepared by solution method can improve the performance of organic thin film transistors (OTFT) prepared by solution method. The adjustment of surface energy can effectively control the drying behavior of ink-jet printing solutions and provide a new way to improve the ink-jet printing of the bottom contact OTFTs. The main research of this paper is to design and construct the asymmetric electrodes of different materials (with different surface energy), and to induce the ink-jet printing solution to form the orientation growth crystallization. The properties of organic thin film transistors are studied. Under this framework, we have studied the specific preparation parameters and methods, and their effects on the induction of asymmetric electrodes and the mechanism of microdynamics. The main contents are as follows: (1) the asymmetric electrode devices with bottom contact gold and silver are prepared, and the drying of semiconductor ink in the channel of this structure is studied. The different contact angles displayed on the substrate of the semiconductor solution ink will break the overall balance between the surface tension and the surface tension at the liquid / air interface. The surface tension in the solution exists in a gradient, which makes the solution from a larger contact angle under the action of the asymmetric Ma Nago flow. The growth crystallization of the channel across the channel is formed and the charge transmission performance at the channel is enhanced. The experimental conditions such as the substrate temperature, channel length, and the distance between the ink-jet printing point are systematically studied. The influence on the film morphology and device performance is analyzed. The contact resistance and the body resistance of the OTFT device are systematically analyzed. The significance of controlling the crystallization of the growth process is true. The OTFTs prepared under the optimal conditions has a nearly 2.5 times higher mobility than the original device. At the same time, the uniformity of the multi device is also promoted by the controlled growth of the film. (2) the graphene film is prepared by chemical vapor deposition (CVD). The process and parameters of the process are studied. Through the characterization of the morphology and electrical properties of the film, the better CH4 gas flow rate is 20 SCCM and the H2 gas flow rate is 20 sccm.. The thin film prepared under the optimal condition is proved to be a high quality monolayer graphene film, which can be used as the device electrode material. The advantages and disadvantages of each method are characterized by the method of characterizing the graphene electrode with the pattern, and the asymmetric electrode device of the bottom contact gold graphene is prepared by the method of first transfer and etching. The active layer of the device is prepared by the ink-jet printing method. The semiconductor ink is induced by the asymmetric substrate to form the crystallization across the channel. In the case of the mismatch between the energy level of the graphene and the semiconductor material, the optimization of the crystal morphology of the device still makes the mobility of the device 2 times higher than that of the original device. The device structure with inducible orientation in this paper has a good compatibility with other methods for improving the performance of the OTFTs. Further research can be tried. Unsymmetrical structure is combined with other methods.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN304.5;TN321.5

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