Research On Solution Process And Output Characteristics Simulation Of Flexible SWNT-TFT

Single walled carbon nanotubes with high mobility and high flexibility had attracted much attention. SWNT-TFT (Single walled carbon nanotube random network thin film transistor, SWNT-TFT), which was fabricated by solution process, inherited the advantages from SWNT. The simple and flexible solution process was suitable for preparation of SWNT-TFT on flexible substrate which couldn’t withstand high temperature, and showed great potential applications in the field of flexible transparent macro-electronics.According to the characteristics of the solution process, we selected polyimide as flexible substrate, Ti/Au as gate materials, Ti/Pd as electrode materials, Al2O3/SiOx as gate dielectric materials,99% semiconducting SWNT solution as material for active layer deposition. After exploration and experiment of key steps, such as polyimide substrate formation, active layer deposition and graphic electrode, complete process was determined finally. A targeted process optimization was proposed after analyzing the output characteristics and transfer characteristics and gate leakage data obtained from test. The optimization included polyimide film forming process, metal lift-off technology and changing gate dielectric to SiOx/Al2O3/SiOx. Issues related solution process, including the problem of low rate of good characteristic TFT and the problem of abnormal characteristic induced by large gate leakage, were resolved and the good performance ratio increased from 6.6% to 30%～37%.Analyzing the performance of w=50μmL=10μm SWNT-TFT, we found the saturation current was about 1.6μA and the current on-off ratio was about 8760. According to the characteristics of SWNT-TFT, we simulated the random distribution of channel SWNT by software called Matlab, and then proposed a current equation which was suitable for SWNT-TFT with low density of SWNT. And found in the simulation when the gate voltage was low, the output characteristic were not affected by the capacity of the gate dielectric, which provided a theoretical reference for flexible applications.