The Research On Organic Thin-film Transistor Fabrication And Device Model

Much more attention has been paid to Organic Thin Film Transistor (OTFT) for its richmaterial sources, low cost and mass production in the recent years. Although previousresearch focusing on OTFT has made some progress, large-scale commercial applications arestill in trouble due to lacking of OTFT proprietary charge transport theory system, fabricationof higher performance of organic semiconductor materials, regulating the threshold voltageand application extension. The paper reports the characteristics of OTFT from both the currentmodel and processing to optimize the device performance as well as simulation.The main results are as follows:(1)A dc current-voltage model and explicit expression of surface potential for OTFTwere proposed，which could explain the influence of the surface potential on the device;(2)The experimental results and new model simulations were compared for high-voltageOTFT, and the conclusions demonstrated that the new model could be used in thehigh-voltage OTFTs.(3)By comparing the results between the experimental data and new model and Locci’smodel simulations for low-voltage OTFT, it showed that new model was better.(4)By analyzing the calculation results of surface potential on source and drainelectrodes, it showed that the maximum value was-0.502V for source electrode between-80Vand-10V.Comparatively, the relative one was-0.3737V from-3.0V to-1.5V. It suggestedthat the surface potential could not be ignored for low-voltage OTFT.(5)Fabrication and characteristics of Tips-pentacene OTFT were implemented by solventvapor annealing (SVA) in another part. By fabricating bottom-gate top contact Tips-pentaceneOTFT and studying the electrical characteristics of the device, the results with a field-effectmobility of0.012cm2/(V.s) and current on/off ratio of350and VTof-5.1V were obtained,which implied that the proposed model was suitable to the device.(6) Comparison between Tips-pentacene OTFT and new model tested the validity of theproposed model. Meanwhile, the calculation results of surface potential on source and drainelectrodes showed that the maximum value was-0.2424V for source electrode between-40Vand-10V.