Large-area and highly uniform carbon nanotube film for high-performance thin film transistors

摘要

Carbon nanotube thin film transistors (CNT-TFTs) are a potential TFT technology for future high-performance macroelectronics.Practical application of CNT-TFTs requires the production of large-area,highly uniform,density-controllable,repeatable,and high-throughput CNT thin films.In this study,CNT films were fabricated on 4-inch Si wafers and 2.5th generation (G2.5) backplane glasses (370 mm ×470 mm) by dip coating using a chloroform-dispersed high-purity semiconducting CNT solution.The CNT density was controlled by the solution concentration and coating times,but was almost independent of the substrate lifting speed (1-450 mm·min-1),which enables high-throughput CNT thin film production.We developed an image processing software to efficiently characterize the density and uniformity of the large-area CNT films.Using the software,we confirmed that the CNT films are highly uniform with coefficients of variance (Cv) ＜ 10％ on 4-inch Si wafers and ～ 13.8％ on G2.5 backplane glasses.High-performance CNT-TFTs with a mobility of 45-55 cn2·V-1·s-1 were obtained using the fabricated CNT films with a high-performance uniformity (Cv ≈ 11％-13％) on a 4-inch wafer.To our knowledge,this is the first fabrication and detailed characterization of such large-area,high-purity,semiconducting CNT films for TFT applications,which is a significant step toward manufacturing CNT-TFTs.