Effects Of The Electrode Modification On The Performance Of Organic Field Effect Transistors

Organic Field Effect Transistor （OFET） have attracted great interest due to theirpotential applications in low-cost, large-area and flexible electronics such as driving activematrix displays, identification cards, sensing devices and electronic paper. In general, theperformance of OFET is not governed solely by materials or structral options, whereas it islargely influenced by electrodes modified layers between the metal source-drain（S/D）electrodes and the organic semiconductors. Therefore, using proper electrode modified layeris an effective way to improve the performance of OFET.In this dissertation, the different development stages，the main application areas and theexisting problems of the OFET in recent decades have been summarized firstly. And thenmaterials and the structure of the devices were introduced. The carrier injection andtransporting mechanism of OFET was Outlined at last.The research Contents is summarized as follows:（1） Pentacene-based OFET with Al S/D electrodes modified by inserting a transitionmetal oxide （V₂O₅） layer were fabricated. The effect on thicknesses of V₂O₅layer was studied.The performance of the devices with V₂O₅/Al S/D electrodes is considerably improvedcompared to the OFET with only Al S/D electrodes. These performance improvements wereascribed to the low carrier injection barrier and the reduction of contact resistance.（2） C₆₀/Pentacene-based ambipolar heterostructure OFET （AOFET） with Al S/Delectrodes modified by inserting a transition metal oxide （V₂O₅） layer were fabricated.Compared with the device without V₂O₅modified layer, the modified device hasdemonstrated good ambipolar characteristics. These performance improvements are ascribedto the presence of V₂O₅layer at the pentacene/Al interface significantly reduces thesource/drain contact resistance, increases the holes injection and make electronic and holeinjection close to balance.（3） Pentacene-based Vertical OFET （VOFET） with Al S/D electrodes modified byinserting a transition metal oxide （V₂O₅） layer were fabricated.The effect on thicknesses ofV₂O₅layer was studied. The performance of the devices with V₂O₅/Al S/D electrodes wereconsiderably improved and reduced fabrication cost for the electrodes of VOFET.（4） Pentacene-based photo OFET （PhotOFET） with Al S/D electrodes modified byinserting a transition metal oxide （V₂O₅） layer were fabricated.The effect of V₂O₅modifiedlayer was studied. The results indicated the absorption and photo/dark current ratio ofPhotOFET increased by inserting V₂O₅modified layer. And all the experience gained byinserting V₂O₅modified layer would form the basis of future research of PhotOFETs...