Li Sizhe, Chen Xue, Liu Li, Zeng Zhiyu, Chang Sheng, Wang Hao, Wu Hao, Long Shibing, Liu Chang
Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, and School of Physics and Technology, Wuhan University, Wuhan 430072, China.
Hubei Nuclear Solid Physics Key Laboratory, and School of Physics and Technology, Wuhan University, Wuhan 430072, China.
J Colloid Interface Sci. 2022 Sep 15;622:769-779. doi: 10.1016/j.jcis.2022.04.016. Epub 2022 Apr 9.
Micro light-emitting diodes (Micro-LEDs) are currently attracting more and more attention. Thin film transistors (TFTs) with micron channel lengths can be used to drive Micro-LEDs. The key parameters of TFTs, such as mobility, I/I and threshold voltage, still need to be improved. In this study, we propose and experimentally demonstrate ZnO TFTs using bilayer electrodes to overcome the short channel effects when the channel length is scaled down to 3 μm. Ti, Mo and Sn interlayers not only serve as diffusion barriers to prohibit migration of Cu atoms from the top electrodes, but also enhance adhesive energy of the metal electrodes on ZnO channel layers. ZnO TFTs using Cu/Ti bilayer electrodes exhibit the best performance, e.g., a high mobility of 45.3 cmVs, a high I/I ratio of 4.28 × 10, a low subthreshold of 0.24 V/dec and a proper threshold voltage of 1.13 V. The high mobility can be attributed to a significant decrease of the barrier height and a slight narrowing of the space charge layer, and the high ratio of I/I is concerned with the high electron concentration under an ON-state condition. Thus, ZnO TFTs using Cu/Ti bilayer electrodes can be used in next-generation displays.
微发光二极管（Micro-LED）目前正吸引着越来越多的关注。具有微米级沟道长度的薄膜晶体管（TFT）可用于驱动Micro-LED。TFT的关键参数，如迁移率、I/I和阈值电压，仍有待提高。在本研究中，我们提出并通过实验证明了使用双层电极的ZnO TFT，以克服当沟道长度缩小至3μm时的短沟道效应。Ti、Mo和Sn中间层不仅作为扩散阻挡层来阻止Cu原子从顶部电极迁移，还增强了金属电极与ZnO沟道层之间的附着能。使用Cu/Ti双层电极的ZnO TFT表现出最佳性能，例如，高迁移率为45.3 cm²V⁻¹s⁻¹，高I/I比为4.28×10，低亚阈值摆幅为0.24 V/dec，合适的阈值电压为1.13 V。高迁移率可归因于势垒高度的显著降低和空间电荷层的轻微变窄，而高I/I比与导通状态下的高电子浓度有关。因此，使用Cu/Ti双层电极的ZnO TFT可用于下一代显示器。
