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科学技术的快速发展使得电子产品的性能飞速提高。传统硅基器件的性能被不断挖掘,在许多领域都表现得十分优异。但是由于其材料自身的物理特性,属于刚性材质[1],限制了其在柔性电子领域的应用。传统电子器件的柔韧性以及可延展性非常有限,无法满足未来电子领域的柔性化发展需求。
相对于传统的硅材料而言,二维材料有其独特的优势。此类材料可以通过将大块材料剥离成小尺寸获得[2],或通过化学气相沉积(Chemical Vapor Deposition, CVD)获得大面积[3]。并且其原子级薄的单层或几层晶体具有强的层内共价键和弱的层间范德瓦尔斯键,从而具有优异的电学、光学和机械性能[4-6]。同时,二维材料中有半导体,导体,绝缘体,使得二维材料在柔性电子领域具有非常大的研究潜力和应用价值。
二维材料具有高的机械拉伸强度[7-8]以及光学透明度,并表现出非常优异的电荷传输性质。以石墨烯(graphene)为例,极高的杨氏模量((1.0±0.1) TPa)[9]、极高的载流子迁移率(15000 cm2/(V·s))[10],是商用硅材料迁移率的140倍。但是由于其零带隙,导致使用graphene作为沟道材料的晶体管有非常严重的漏电现象而导致极低的开关比,限制了其在晶体管领域的应用。虽然graphene作为沟道材料存在上述问题,但其超高的迁移率使得电阻非常小,可以较好地作为二维电极。而二维过度金属硫化物(TMDCs)恰好能够弥补graphene零带隙的缺点,例如,单层的二硫化钼(MoS2)的禁带宽度为1.9 eV[11-12],可以作为沟道材料。除此之外,二维材料中还有禁带宽度较大的材料可以作为绝缘体材料,例如六方氮化硼(h-BN),属于宽禁带半导体(5.0 eV~6.0 eV),可以作为栅介质层或者保护层[13-14]。
由此,本文使用graphene,MoS2,h-BN在聚对苯二甲酸乙二醇酯(Polyethylene Terephthalate, PET)上制备了基于二硫化钼的柔性场效应晶体管。同时,采用柔性测试平台,测试了器件的柔性电学特性。
Characterization of Electrical Properties of Flexible Transistors Based on van der Walls Heterostructure under Dynamic Strain Modulation
doi: 10.12178/1001-0548.2023104
- Received Date: 2023-04-21
- Accepted Date: 2023-05-19
- Rev Recd Date: 2023-05-29
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Key words:
- two-dimensional material /
- field effect transistors /
- flexible devices /
- electrical characteristics
Abstract: Conventional electronic devices are mainly composed of inorganic semiconductor materials such as silicon-based and rigid polymer insulating substrate materials, which are the basis of existing electronic technology. Although the traditional electronic technology has been developed, but due to the limitations of the material, resulting in the field of flexible electronics, its application still exists in a certain limit. Two-dimensional materials have high crystallinity, near-perfect lattice structure, atomic-level thickness and high mechanical tensile strength, and exhibit excellent charge-transfer properties, making them promising for applications in the field of flexible electronics. In this paper, we combine the excellent mechanical properties of graphene, molybdenum disulfide and hexagonal boron nitride to prepare molybdenum disulfide-based field-effect transistors by mechanical exfoliation method with dry transfer. We test the flexible electrical properties of the devices using a flexible test platform built in-house. The test results show that the designed two-dimensional heterojunction transistor has only a small change in electrical properties under static test conditions; however, under dynamic test conditions, due to the too small van der Waals force between layers, the sliding or displacement between layers makes the electrical properties of the device change significantly.
Citation: | CHEN Jianglong, WANG Zenghui. Characterization of Electrical Properties of Flexible Transistors Based on van der Walls Heterostructure under Dynamic Strain Modulation[J]. Journal of University of Electronic Science and Technology of China. doi: 10.12178/1001-0548.2023104 |