有机场效应晶体管导电机制及其稳定性研究

Charge transport mechanism and stability in pentacene thin-film transistors

并五苯薄膜和单晶晶体管研究是目前有机电子学研究领域的热点.本文通过实验和理论模型系统研究了并五苯有机小分子薄膜的初始生长层形貌结构对有机薄膜晶体管器件电学性能的影响.提出单层薄膜二维晶粒边界模型,揭示了初始生长层晶粒大小对晶体管器件载流子迁移率及栅极偏压下阈值电压移动量的影响.同时,通过理论拟合计算得出有机晶体管器件结构在现有实验条件中的一些重要参数,如晶粒单畴中的迁移率、晶粒边界中缺陷浓度和缺陷势垒高度等.这些知识加深了对薄膜结构与器件性能之间关联的理解,为进一步改善并五苯薄膜晶体管器件性能提出明确的方向.此外,本文还提出一种新的并五苯单晶生长方法,即从并五苯单层膜在惰性常压气氛中熟化开始,通过两步法生长出高质量大尺寸的并五苯单晶.我们系统探讨了并五苯单层膜向单晶转变时的分子热力学、动力学过程,为后续单晶体器件的研究奠定了基础.

The research of pentacene thin-film transistors （TFFs） and pentacene single crystal has been the research focus recently. In this paper, we have performed both experimental and theoretical studies for the influence of morphology of the first pentacene layer on the electronic properties of TFTs. We proposed a two-dimensional grain boundary model to interpret the relationship of the mobility as well as threshold voltage shift under gate bias-stress and the first-layered grain size. We obtained several meaningful parameters, such as mobility in single grain, trap density in grain boundary and the height of potential barrier. This is meaningful to optimize the performance of organic thin-film transistors. Meanwhile, we raised a new strategy to prepare pentacene single crystal, which starts from pentacene monolayer film and the process can be defined as two step growth of high quality, large pentacene single crystals. We systematically studied the molecular dynamics in this process, which may make essential preparation for device fabrication in the future.