近期，本课题组张敏老师和张艺明同学分别以通讯作者和第一作者在材料领域国际知名期刊Advanced Functional Materials（SCI一区，2022年IF=19.924）上发表了题为“Mixed-Dimensional van der Waals Engineering for Charge Transfer Enables Wafer-Level Flexible Electronics”的研究成果。
该研究揭示了范德华工程及低维全碳基结构在实现高性能电子器件方面的优势，实现了具备优异电学和机械性能的柔性电子器件，并研究了其中的电荷转移机制。
该工作提出并通过混合维度范德华工程制备了晶圆级柔性全碳基晶体管。其中，一维半导体型碳纳米管作为沟道，一维金属型碳纳米管作为源/漏/栅电极，二维氧化石墨烯作为栅介电层。该晶体管具有优异的电学特性，亚阈值摆幅最低可至51.8 mV dec-1，突破了传统器件的玻尔兹曼热力学极限。同时，该晶体管的最高迁移率可高达313.8 cm2V-1s-1，具有高载流子传输速率、小回滞和低工作电压等优势。通过密度泛函理论计算和电学表征，该工作进一步证实了氧化石墨烯对碳纳米管的电荷转移调制效应，该效应增强了碳纳米管的沟道电导。此外，晶体管在250 μm的超小半径弯折后仍保持稳定的电学特性。基于该器件结构，该工作还实现了指数级灵敏度的温度传感器概念和反相器模块，展示了该晶体管作为全范德华柔性电子构建基础模块的可行性。无论是全范德华晶体管实现策略还是电荷转移机制，都为提高器件性能和进一步推进柔性电子发展提供了通用方法。
Flexible electronics draw intense interest because of their promising potential for emerging applications, which, however, encounter challenging obstacles of material self-limiting fabrication, trade-off mechanical flexibility, and associated moderate electrical performance. Here, wafer-level flexible fully-carbon-integrated transistors via mixed-dimensional van der Waals (vdW) engineering are realized. Remarkable performance includes subthreshold swing of 51.8 mV dec−1 breaking thermionic limit, outstanding field-effect mobility as high as 313.8 cm2 V−1 s−1, and sub-1 V operating voltage. The charge transfer modulation of graphene oxide on carbon nanotube in the vdW-integrated transistors is designed to enhance channel conductance, which is simultaneously confirmed by theoretical calculations and electrical characterizations. Besides, the transistors maintain stable electrical performance after bending under an ultra-small radius of 250 µm. Exponential-sensitivity temperature sensors and binary-logic inverters are further realized to demonstrate the feasibility of the devices as the building blocks of all-vdW electronics. These results indicate that either the strategy of all-vdW transistor realization or the charge transfer provides general approach to improve device performance and further advance flexible electronic technologies.
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