Large-area and highly uniform carbon nanotube film for high-performance thin film transistors
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 cm2·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.
Keywordscarbon nanotube thin film large area uniform transistor
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This work was supported by the National Key Research and Development Program (No. 2016YFA0201902), the National Natural Science Foundation of China (No. 61621061), Beijing Municipal Science & Technology Commission (Nos. Z171100002017001 and Z161100000216146), and Chinese Academy of Science (No. YZ201671). The authors thank Dr. Wei He from Focus e-Beam Technology Co., Ltd. for helpful discussion on high throughput SEM technology. We also thank Prof. Shimin Hou and Dr. Hao Wang for valuable discussion.
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