State Key Laboratory of Precision Measurement Technology and Instruments, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, No. 92 Weijin Road, Tianjin, 300072, China.
Nanoscale. 2018 Jul 9;10(26):12436-12444. doi: 10.1039/c8nr02668h.
Transition metal dichalcogenides (TMDCs) have recently become spotlighted as nanomaterials for future electronic and optoelectronic devices. In this work, we develop an effective approach to enhance the electronic and optoelectronic performances of WSe2-based devices by N2O plasma treatment. The hole mobility and sheet density increase by 2 and 5 orders of magnitude, reaching 110 cm2 V-1 s-1 and 2.2 × 1012 cm-2, respectively, after the treatment. At the same time, the contact resistance (Rc) between WSe2 and its metal electrode drop by 5 orders of magnitude from 1.0 GΩ μm to 28.4 kΩ μm. The WSe2 photoconductor exhibits superior performance with high responsivity (1.5 × 105 A W-1), short response time (<2 ms), high detectivity (3.6 × 1013 Jones) and very large photoconductive gain (>106). We have also built a lateral p-n junction on a single piece of WSe2 flake by selective plasma exposure. The junction reaches an exceedingly high rectifying ratio of 106, an excellent photoresponsivity of 2.49 A W-1 and a fast response of 8 ms. The enhanced optoelectronic performance is attributed to band-engineering through the N2O plasma treatment, which can potentially serve as an effective and versatile approach for device engineering and optimization in a wide range of electronic and optoelectronic devices based on 2D materials.
过渡金属二硫属化物 (TMDCs) 最近成为未来电子和光电子器件的纳米材料的焦点。在这项工作中，我们通过 N2O 等离子体处理开发了一种有效提高基于 WSe2 的器件的电子和光电子性能的方法。处理后，空穴迁移率和薄层密度分别增加了 2 个和 5 个数量级，达到 110 cm2 V-1 s-1 和 2.2 × 1012 cm-2。同时，WSe2 与其金属电极之间的接触电阻 (Rc) 从 1.0 GΩ μm 降低到 5 个数量级，为 28.4 kΩ μm。WSe2 光电导器件表现出优异的性能，具有高响应率 (1.5 × 105 A W-1)、短响应时间(<2 ms)、高探测率 (3.6 × 1013 Jones) 和非常大的光电导增益 (>106)。我们还通过选择性等离子体暴露在单个 WSe2 薄片上构建了横向 p-n 结。该结达到了非常高的整流比 106、优异的光响应度 2.49 A W-1 和 8 ms 的快速响应。增强的光电性能归因于 N2O 等离子体处理的能带工程，这可能成为基于二维材料的各种电子和光电子器件的器件工程和优化的有效且通用的方法。
