Studies On Organic Field-effect Transistors Based On Pentacene/P13

With the rapid development of IT, large scale integrated circuits (LSI) technology and active-driven organic display technology have become more and more important. Organic field-effect transistors have many advantages which provide large area flexible flat panel displays and LSI a new solution.In this thesis, we fabricated the unipolar and ambipolar organic field-effect transistor devices based on the insulating material PMMA, electron transport material P13and hole transport material pentacene. We studied the influences of the insulating layer, ratio of width to length of the carrier transfer channel and the thickness of the active layer on the device performance. The results are as follows:Firstly, we fabricated the organic insulating PMMA thin films of the different thickness. The PMMA film is530nm thick under the conditions of60mg/ml PMMA in ethyl acetate solution, spin-coating time15s, and spin-coating speed600r/min. The AFM images show that the PMMA films are uniform and dense. The result shows that the performance of the OTFT device with the710nm PMMA layer is better.Secondly, we designed the masks of different ratios of width to length of the channel by AutoCAD software. We inestigated the influence of the ratio of width to length of the chanel on the performance of the pentacene OTFT devices and found that with the increase of the ratio the threshold voltage decreased, while Ion/Ioff and the carrier mobility were lessly affected.Thirdly, we fabricated the N-type unipolar OTFT devices based on P13. The device with P13of50nm showed better performance in threshold voltage, Ion/Ioff as well as carrier mobility.Finally, based on optimization of each functional layer, we studied the ambipolar OTFT device based on pentacene and P13. The device showed saturated drain-source current in both VGS>0V, VGS<0V regions, and good ambipolar characteristic.