Organic Semiconductor Thin-films And Single-crystal For Electronic Devices

With the rapid development of modern electronic information technology, theelectronic circuit based on traditional inorganic semiconductor materials seems difficultto satisfy the critical requirements in the visible future. A new era of semiconductorscience and technology has been coming with the invention of organic semiconductormaterials. Organic semiconductor devices and circuits can possess some desirableproperties such as good flexibility and high optical transparence due to the intrinsicfeatures of organic materials. Furthermore, most organic semiconductors can be easilyprepared as the state of liquid phase due to its solubility, widely enriching the potentialapplication of the organic electronic devices and circuits.In this study, we chose different kind of organic semiconductors in the form of thinfilm or single crystal, and tried to assemble several organic devices for variousfunctions and improved performance. The main contents are described below:Firstly, we developed a way to modify the interface between organicinsulating/dielectric layer and semiconductor layer of organic thin film field-effecttransistors by introducing a single monolayer as the buffer layer. It was found that thecoating of OTS or OTMS monolayer could obviously promote the performance of thecorresponding transistor despite that the semiconductor is pentacene or CuPc, whichmight be attributed to the reduced contact resistance, the optimized orientation of thecrystal, and so on.Secondly, BPEA organic single crystal was applied to construct field-effecttransistor and more complex devices such as phase inverter. The photolithography wasdeveloped to build the pattern of the bottom-contact metal electrodes, and BPEA seedswere used to guide the growth direction of BPEA single crystals. The combinedmethodology could result in the controlled align of BPEA single crystal nanowires withthe length over100um, which rendered the possibility to form more than10transistorsby using the same single crystal. This straightforward hybrid method could furtherminimize the dimension of the single transistors and increase the integration degree ofthe circuits, offering more complex functions in the future. At last, we tried to prepare FLASH memory by adopting organic thin filmconductor or organic single crystal, which demonstrated the information storageproperty. The preliminary investigation indicates that the performance can be furtherpromoted.