Construction of High Field-Effect Mobility Multilayer MoS2 Field-Effect Transistors with Excellent Stability through Interface Engineering
Construction of High Field-Effect Mobility Multilayer MoS2 Field-Effect Transistors with Excellent Stability through Interface Engineering
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DOI：
10.1021/acsaelm.0c00347
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发表时间：
2020-06
期刊：
影响因子：
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通讯作者：
Jianfeng Jiang;Yu Zhang;Aizhu Wang;Jiazhi Duan;Hao Ji;Jinbo Pang;Y. Sang;Xianjin Feng;Hong Liu-Ho
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文献类型：
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作者：
Jianfeng Jiang;Yu Zhang;Aizhu Wang;Jiazhi Duan;Hao Ji;Jinbo Pang;Y. Sang;Xianjin Feng;Hong Liu-Ho
二维（2D）材料场效应晶体管（fet）的电稳定性和场效应迁移率对于实际电子应用非常重要。介电介质与二维材料之间的界面对二维材料在传输过程中的界面散射具有重要的影响，这一直是一个严峻的挑战。早期的工作已经取得了优异的迁移率和开/关比，但对二硫化钼器件电稳定性的认识和提高还处于起步阶段。本文提出了一种简单有效的策略，通过自旋涂覆聚甲基丙烯酸甲酯（PMMA）双层来提高二硫化钼（MoS2）场效应迁移率和电稳定性，其中MoS2下面的PMMA与SiO2一起作为栅极介质，MoS2上面的PMMA用于保护FET通道免受空气暴露。采用PMMA/SiO2作为后门介电介质和PMMA封装层，将场效应电子迁移率从41.8 cm2/Vs提高到104.6 cm2/Vs，提高了2.5倍。与时间和应力相关的电稳定性得到了本质上的改善。在±35 V的栅极偏置电压下施加300 s，即使在露天储存45天后，也可以实现可忽略不计的阈值电压偏移（ΔVth < 0.1 V）和场效应迁移率下降（1.4%）。有效抑制位于沟道界面的界面杂质有助于提高MoS2场效应管的电学性能。此外，利用密度泛函理论（DFT）建立了一个理论模型来研究不同的MoS2/介电界面结构，该模型与界面散射理论是一致的。该研究不仅为高性能二维场效应管的制造提供了线索，而且为了解二维材料族器件的电性能退化机制提供了机会，推动了其在二维器件和柔性电子中的实际应用。
Electrical stability and field-effect mobility of two-dimensional (2D) material-based field-effect transistors (FETs) are extremely important for practical electronic applications. Interface scattering during the transmission of 2D materials, which can be significantly influenced by the interface between dielectric and 2D materials, remains a formidable challenge. Early work has achieved excellent mobility and on/off ratio, but the understanding and improvement of the electrical stability of MoS2 devices are still in their infancy. Herein, a facile and effective strategy is proposed via a spin-coated polymethyl methacrylate (PMMA) dual layer to enhance both field-effect mobility and electrical stability of molybdenum disulfide (MoS2) FETs, in which the PMMA underneath MoS2 works as a gate dielectric together with SiO2 and the PMMA on top of MoS2 is used to protect the FET channel from exposure to air. The field-effect electron mobility has been improved up to 2.5 times, from 41.8 to 104.6 cm2/Vs, by using PMMA/SiO2 as the back gate dielectric and PMMA capsulation layer. The time- and stress-dependent electrical stability has been essentially improved. A negligible threshold voltage shift (ΔVth < 0.1 V) and field-effect mobility degradation (1.4%) are achieved upon a gate bias voltage of ±35 V applied for 300 s, even after 45 day storage in open air. The effective suppression of interface impurities located at the channel interface contributes to the electrical performance enhancement of MoS2 FETs. Furthermore, a theoretical model was developed to investigate different MoS2/dielectric interface structures by density functional theory (DFT), which is consistent with interface scattering theory. This study not only provides a clue for the high-performance 2D FET fabrication but also offers an opportunity to understand the electrical property degradation mechanism of the 2D material family devices, pushing forward their practical applications in the 2D devices and flexible electronics.