Growth of 2D Electronics: Development of Van Der Waals Heterostructures for Flexible and Transparent Electronics.

二维电子学的发展：用于柔性透明电子学的范德华异质结构的开发。

• 批准号: 2436110
• 金额: --
• 依托单位: University of Bath
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2436110
• 关键词: Growth; 2D; Electronics; Development; Van

Electrically conductive 2D materials are currently of great interest due to their potential for use in flexible electronics and miniaturisation to the sub-nanometre level. Currently, photolithography methods utilise light to etch a pattern into these materials to fabricate electronic devices. However, the diffraction limit of light limits the minimum resolution of these top-down devices to 7 nm. As such, new materials that can be synthesised in a bottom-up fashion are required to create smaller electronic devices. Graphene, first isolated in 2004, has been of great interest recently due to its electrical properties. As a single atom thick layer of hexagonally bonded carbon atoms, it is the thinnest known material, making it very mechanically flexible. Pristine graphene is also one of the best-known electrical conductors. However, despite Graphene's outstanding material properties, it has one major drawback. Its lack of a bandgap means it cannot be used to fabricate transistors, since it cannot maintain an off state due to its metal-like conductivity. Despite this, Graphene remains attractive for use in the next generation of electronic devices due to its synergy with another class of semiconducting 2D materials, the Transition Metal Dichalcogenides (TMDs).TMDs are a class of materials that follow the general formula MX2, where M is a transition metal (W and Mo in this research) and X is a chalcogen, an element from group 16 of the periodic table (S in this research). These materials are semiconducting; they support a bandgap but still have the potential to be electrically conductive when excited. This allows them to maintain an off state until a stimulus is applied, at which point they become electrically conductive. This makes them perfect for use in transistors, especially since these materials show potential for bottom-up synthesis. A monolayer of TMD material consists of a metal atom sandwiched between two chalcogen atoms and have thicknesses below the nanometre scale (MoS2 0.7 nm, WS2 0.8 nm). Although TMDs do not exhibit conductivities as high as that of Graphene, the two materials could be used in conjunction with one another to form a so-called Van der Waals heterostructure, a layered structure of two different materials held together by Van der Waals forces. Such heterostructures could allow for the production of electronics with Graphene like conductivities, but TMD like on/off control.The initial aim of this work is to synthesise high quality monolayers of MoS2 and WS2 using Chemical Vapour Deposition methods, such as Metal-Organic CVD and Plasma Enhanced CVD, from known precursor molecules. Following a successful deposition, the synthesis of functional heterostructures will be explored, as well as the potential for development of new precursor molecules to control properties of the monolayers. The final goal of the project is to develop a series of new 2D heterostructure materials, ultimately to be supported on mechanically flexible substrates, that can be used in a multitude of electronic applications and drive forward miniaturisation while maintaining, or improving on, the electrical properties of current 2D electrical materials.

导电2D材料由于其在柔性电子产品中的应用潜力和亚纳米级的微结构化，目前引起了极大的兴趣。目前，光刻方法利用光将图案蚀刻到这些材料中以制造电子器件。然而，光的衍射极限限制了这些自上而下器件的最小分辨率为7 nm。因此，需要能够以自下而上的方式合成的新材料来制造更小的电子设备。石墨烯于2004年首次分离出来，由于其电学性质，最近引起了极大的兴趣。作为一个单原子厚的六边形键合碳原子层，它是已知最薄的材料，使其非常具有机械柔性。原始石墨烯也是最知名的电导体之一。然而，尽管石墨烯具有出色的材料特性，但它有一个主要缺点。它缺乏带隙意味着它不能用于制造晶体管，因为它不能保持关闭状态，由于其金属般的导电性。尽管如此，石墨烯由于其与另一类半导体2D材料（过渡金属二硫属化物（TMD））的协同作用而对于在下一代电子器件中的使用仍然具有吸引力。TMD是一类遵循通式MX2的材料，其中M是过渡金属（本研究中的W和Mo）和X是硫族元素，周期表第16族的元素（本研究中的S）。这些材料是半导体的;它们支持带隙，但在激发时仍然具有导电的潜力。这使它们能够保持关闭状态，直到施加刺激，此时它们变得导电。这使得它们非常适合用于晶体管，特别是因为这些材料显示出自下而上合成的潜力。TMD材料的单层由夹在两个硫族原子之间的金属原子组成，并且具有低于纳米尺度（MoS 2 0.7 nm，WS 2 0.8 nm）的厚度。虽然TMD不表现出与石墨烯一样高的电导率，但是这两种材料可以彼此结合使用以形成所谓的货车德瓦尔斯异质结构，即通过货车德瓦尔斯力保持在一起的两种不同材料的层状结构。这种异质结构可以允许生产的电子与石墨烯一样的导电性，但TMD一样的开/关控制。这项工作的最初目的是合成高品质的单层二硫化钼和WS 2使用化学气相沉积方法，如金属有机化学气相沉积和等离子体增强化学气相沉积，从已知的前体分子。在成功沉积之后，将探索功能异质结构的合成，以及开发新的前体分子以控制单层性质的潜力。该项目的最终目标是开发一系列新的2D异质结构材料，最终将被支持在机械柔性衬底上，可用于多种电子应用，并在保持或改善当前2D电气材料的电气性能的同时推动电子化。