【作者】 张贺丰；

【导师】 印寿根； 邓家春；

【作者基本信息】 天津理工大学 ， 凝聚态物理， 2006， 硕士

【摘要】 近年来有机发光显示技术及其应用的迅速发展使人们对有机半导体材料和器件有了新的认识。有机场效应晶体管是利用改变电场来控制固体材料导电能力的有源器件,与柔性衬底结合可以制作柔性器件,可以广泛地应用在电子书和柔性平板显示器的有源矩阵驱动电路中。但是目前的有机场效应晶体管存在诸如工作电压高、场效应迁移率和开关电流比率较低等问题,还无法在晶体管市场上取得一席之地,所以有必要从开发新材料、缩短器件的电子沟道和实现单晶内载流子输运等方面来研究并提高器件的各项性能。本文研究了有机极性材料---2-（4-苯酚）-5-嘧啶醇（简称嘧啶醇）的电流/场效应特性。内容分为三部分（1）液态场效应晶体管（2）薄膜态有机场效应晶体管和（3）多晶态有机场效应晶体管。各部分内容都研究了器件的制作和性能,并且给出了相应的定性模型。在制作和研究液态有机场效应晶体管的过程中,我们把有机极性材料嘧啶醇溶于N,N-Dimethylformamide（简称DMF）溶液中,在栅极电场的作用下通过溶液的电流出现了振荡现象。我们详细地研究了栅极电压、源极和漏极电压、源极和漏极间隔以及并联电阻等参数对器件电流的影响。我们根据器件所表现出来的这些性能提出了用于定量解释器件工作机制的液态极性分子模型。在制作和研究薄膜态有机场效应晶体管的过程中,我们使用薄膜态有机极性材料嘧啶醇作为器件的电子沟道,使用掩膜蒸镀法制作了长度是20μm、宽度是10mm的电子沟道。在测量器件的性能时我们发现了不同的三种晶态形貌结构具有不同的I_DS-V_DS性能曲线,同时出现了三种异常的电流效应,包括正常的有机场效应晶体管I_DS-V_DS性能曲线,由栅极电压VG控制的电池效应和多次测量后器件的场效应性能消失。在制作和研究多晶态有机场效应晶体管的过程中,我们使用多晶态有机极性薄膜嘧啶醇作为器件的电子沟道。为了避免周围大气环境对器件性能的影响,我们在真空系统中实现有机极性薄膜的结晶过程、金属电极的制作过程和器件的测量过程。在制作源极和漏极时,我们采用电迁移熔断法制作了长度小于100nm、宽度是0.1mm的电子沟道。在沉积有机极性薄膜时,我们采用在加温衬底上沉积并且用有机溶剂对有机薄膜层进行原位处理的技术形成了多晶态有机极性薄膜:针状、树枝状和块状。在对器件进行测量后我们发现具有不同的晶态形貌结构的器件也会出现不同的I_DS-V_DS性能曲线,而且也出现了三种异常的电流效应,包括正常的有机场效应晶体管I_DS-V_DS性能曲线,由栅极电压VG控制的电池效应和多次测量后器件的场效应性能消失。也就是说,两种晶态有机场效应晶体管的工作性能是一致的,这恰恰证明了这些异常的电流效应是晶态有机极性薄膜用作有机场效应晶体管的电子沟道后所表现出来的自身固有的性能。最后,我们根据这些器件的性能提出了用于定性解释器件工作机制的有机极性晶粒模型。更多还原

【Abstract】 Recent progress in organic electroluminescence display technology has led to a new stage of the research of organic semiconductor. Organic field effect transistor (OFET) is an active device to control the conductibility of solid state material with the change of electrical field, and can be used for active matrix drive circuit in electron paper and flexible flat panel display. However, some problems such as higher operating voltage, lower field effect mobility and on/off ratio, have hindered its further development. So it is very necessary to advance various performances by obtaining the novel materials, shortening the channel length, and achieving highly ordered structure and arrangement in organic thin film.In this thesis, we fabricated and researched organic field effect transistor (OFET) with organic polarizable material 2-(4-hydroxyphenyl)-5-pyrimidinol, including liquid OFET, bulk crystal OFET and thin film crystal OFET. The qualitative operating modes in these devices used for explaining the performance were proposed in detail.During the fabrication and research of liquid OFET, the phenomenon of current vibration was presented with the applied gate voltage when the current flowed through organic polarizable material 2-(4-hydroxyphenyl)-5-pyrimidinol dissolved in N,N-Dimethylformamide (DMF) solution. We observed the change of periodical time in current vibration with the different gate voltage, the different voltage between source electrode and drain electrode, the different channel length, and the different resistance parallel-connected with the device. According to these performances, we presented a qualitative liquid polarizable molecule mode used for explaining current vibration.We fabricated and studied thin-film-crystal OFET with organic polarizable thin film of 2-(4-hydroxyphenyl)-5-pyrimidinol. The patterning technique of shallow evaporation was used for the fabrication of electron channel as long as 20μm and as wide as 10mm. After accomplishing the measurement for the device, we found three types of device performance with the different morphology. Also, we observed the anomalous electrical properties of the devices, including the normal IDS-VDS curves of OFETs, the battery properties of the devices controlled by the applied VG, and the disappearance of the field effect performance when the sample was measured many times.In addition, we fabricated and studied polycrystal OFET with the same organic polarizable material as the above device. To avoid the influence of the ambient atmosphere on the device performance, the crystal process of organic polarizable thin film, the fabrication of metallic electrodes and the measurement for the device were accomplished in the vacuum thermal evaporation system. The electron channel with the length of less than 100nm and the width of 0.1mm was fabricated by electromigration. The deposition at high substrate temperature and in situ postdeposition annealing with the help of in situ treatment of acetone for organic thin film were used for forming crystalline thin film. The device exhibited the similar performance with the above thin-film-crystal OFET. Based on these device performances, we proposed a qualitative organic polarizable crystalline grain mode to explain the above phenomenon.更多还原