Significant performance and stability improvement of low-voltage InZnO thin-film transistors by slight La doping

• Published in: Applied physics letters Vol. 121; no. 6
• Main Authors: Cai, Wensi, Li, Mengchao, Li, Haiyun, Qian, Qingkai, Zang, Zhigang
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 08.08.2022
• Subjects: Applied physics; Backplanes; Carrier density; Electric potential; Semiconductor devices; Stability; Thin film transistors; Transistors; Voltage
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/5.0100407

Low-voltage, solution-processed oxide thin-film transistors (TFTs) have shown great potential in next-generation low-power, printable electronics. However, it is now still quite challenging to obtain low-voltage oxide TFTs with both high mobility and stability, especially for solution-processed ones. In this work, La-doped InZnO (IZO:La) channel for high performance and stable TFTs is developed using a simple solution process. The effects of La composition in IZO:La on the film and TFT performance are systematically investigated. It is confirmed that the incorporation of appropriate La could control the carrier concentration, improve the surface morphology, and passivate the oxygen-related defects, leading to a reduced trap density both at dielectric/channel interface and within the channel layer. As a result, the optimized TFTs with 1% La dopants exhibit the best overall performance, including a low operating voltage of 1 V, a high mobility of 14.5 cm2/V s, a low subthreshold swing of 109 mV/dec, a turn-on voltage close to 0 V, and negligible changes of performance under both positive and negative bias stresses. This work might support the development of all-solution-processed oxide TFT backplanes for battery-powered active-matrix displays.