Prepared And Research Of Organic Field-effect Transistors With Laminated Structure

Organic field-effect transistors(OFET),namely organic thin film transistors (OTFT),is one of the most important research subjects in organic electronics.With the advantages of novelty,low cost and flexibility,OFET had developed rapidly, which provides the best solution schemes to achieve large area and flexible flat displays array and integrated circuits.It has become an important leading topic in organic electronics.In this dissertation,the organic field effect transistor with laminated structure were fabricated with channel length reduced to nanometers.The results are as follows:Firstly,in order to investigate the relationship of films structure with preparation technology,we choosed CuPc as organic material and prepared two samples with structures of Si/SiO₂/CuPc and Si/SiO₂/Al/CuPc by vacuum evaporation coating with the different substrates Si/SiO₂ and Si/SiO₂/Al.we analysed the crystal structure and morphology of the thin films through XRD and SEM.The XRD results show that two CuPc thin films on two substrates both have a wide peak at 2θ=6.9°,which indicates that the films are polycrystalline;the average size of the crystallites in the two films are nearly equal,about 15.822nm.The SEM results show that both films all have well-defined morphology,high degree of smoothness,large grain and flat surfaces. The CuPc thin films have good performance.In addition,the method of measuring the thickness of film by ultraviolet & visible absorption spectrum is introduced.Secondly,we fabricated the organic field-effect transistor with laminated structure on silicon after thermal oxidation,using CuPc as the active layer by vacuum coating.The measured output characteristic curves showed that the device exhibits unambiguous characteristics of field effect.V_G has great influence on I_DS. Investigation on the temperature characteristics shows that with same V_DS,the higher the T,the bigger the I_DS.The reason is:with the increases of T,the hole concentration in the organic layers increases,carrier concentration enlarges while carrier mobility increases.It can be seen that the temperature has a significant impact on the OFET.