标题: | 有机薄膜电晶体后退火之影响研究 The Post-Annealing Effect on Organic Thin-Film Transistors |
作者: | 施尹婷 陈方中 显示科技研究所 |
关键字: | 五环素;有机薄膜电晶体;后退火;pentacene;OTFTs;post-annealing |
公开日期: | 2006 |
摘要: | 在有机材料中,载子的传递主要是以载子跃迁的方式进行,迁移率受限于元件制程中有机薄膜品质的好坏。较差的成膜品质会使得有机薄膜电晶体之载子移动率无法有效提升,因此如何在元件制程中提升薄膜品质一直是非常重要的议题。本研究之主要目的在于探讨元件热退火处理对有机薄膜电晶体之元件特性的影响和元件效能改善的机制,并探讨热退火处理如何影响有机半导体层-pentacene-之成膜品质。 实验结果显示,有机薄膜电晶体经由元件热退火处理后,元件的迁移率由原先的0.42 cm^2/V-s提升至0.8 cm^2/V-s,其中的原因部分来自于热退火处理使得元件的通道电阻大幅下降。另外,透过原子力显微镜我们证明pentacene通道部分的晶界,在热退火处理后有减少的趋势,我们推测这是造成通道电阻下降的主因。然而,热退火处理却使得元件的接触电阻和半导体层中垂直于通道部分的电阻上升了。其内部机制,我们也进一步由原子力显微镜和X光绕射仪的分析结果来探讨。另外,我们也发现当我们结合poly-a-methylstyrene表面修饰及元件后退火效应,可以使得元件的interface traps大幅下降,而且pentacene和基板表面的附着变的更好,进而使得元件迁移率由0.11 cm^2/V-s提升到0.8 cm^2/V-s。 Charge transport in organic semiconductor is typically described by hopping of charges between localized states. For this type of transport, the charge carriers are easily trapped at the grain boundary or by the disorder and impurities around the grains, resulting in the limitation of organic thin-film transistors (OTFTs) device mobility. Therefore, how to improve organic thin film quality becomes a very important issue. Based on the principle of controlling the growth of pentacene film, the effect of post-annealing treatment on pentacene-based TFTs is investigated in this study. Aims of our researches are to examine the effect of post-annealing treatment on device performance, pentacene crystal structures, and their correlations. It is found that the device mobility is increased from 0.42 to 0.80 cm^2/V-s, which results from the reduced channel resistance. Images of atomic force microscopy (AFM) show that it is because the pentacene grain boundaries are reduced after thermal annealing. However, both contact and bulk resistances are slightly raised after post-annealing treatment. The mechanisms are further discussed by the investigation of the X-ray diffraction spectra and AFM patterns. In addition, the device mobility can be improved from 0.11 to 0.8 cm^2/V-s by combining PaMS modification and the post-annealing treatment. It is because that traps in pentacene/insulator interface are significantly moved and the adhesion between pentacene and insulator are improved. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT009415515 http://hdl.handle.net/11536/81040 |
显示于类别: | Thesis |
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