Ferroelectric gating for agile and reconfigurable 2D electronics

智能技术正在渗透到我们的日常生活中。从医疗保健到交通运输再到娱乐，适应我们欲望的电子产品正变得无处不在。对于电子硬件，这为响应迅速、灵活的下一代技术的设计创造了拉力，这些技术可以提供快速、灵活和多功能的设备。为了实现电子功能，电压被用来控制材料的电学属性，改变通道的导电性，以创建晶体管、二极管、存储元件等，其功能与设备的几何形状有关。电气设备的性能既取决于用于导电通道的材料，也取决于电压与其耦合的方式。类似的设备也被用来探索材料中电子相互作用的基本物理，其中可以使用电压来控制材料中的电荷载流子的数量，以便研究它们之间的相互作用的影响。这些相互作用可能导致新的相，例如非传统的超导或从金属行为到绝缘行为的可逆转变，这为先进电子提供了新的机会。因此，器件的功能与先进功能材料的设计和集成有关，以产生导电通道的最佳物理特性及其与施加的控制电压的最有效耦合。对于传导通道，二维材料(2DM)是最令人兴奋的研究领域之一，也是英国真正处于世界领先地位的领域。现在有各种各样的2DM大家族，具有金属、半导体、绝缘、磁性、超导和更多特性。由于它们在原子上很薄，外部电压对2 DM中的所有原子的影响都是一样的，比起传统的三维材料，可以更明确地控制导电性。耦合到外部电压，加上对施加电压模式的空间控制，可以用来制造高效的发光二极管、晶体管和存储元件。可实现的通常受限于与外部电压的耦合。铁电提供了动态控制这种耦合的潜力，具有纳米级的空间分辨率和快速的开关。铁电体具有自发极化，具有很大的表面净电荷，组织在表面电荷为正或负的纳米尺度区域中。如果将2DM放置在铁电体上，并且它们之间的界面干净，这种表面电荷可以通过改变2DM中的电荷载流子的数量来显著改变2DM的电子性质。通过动态控制铁电体中的磁畴结构，可以形成快速灵活的2D电子学。不幸的是，尽管已经制作了原理验证器件，但铁电材料和2 DM之间的有效耦合还没有实现。我们的团队是唯一适合解决这一挑战的人，开发了集成2 DM和铁电材料的优化工艺，并展示了基于移动和切换铁电材料中的磁区的灵活的新电子学。通过这样做，我们将把两个重要的领域结合在一起，充分发挥每个领域的潜力，创造一个新的领域，为探索基础物理和开发新的电子学提供新的机会。

Smart technologies are infiltrating our daily lives. From healthcare to transport to entertainment, electronics that adapt to our desires are becoming ubiquitous. For electronics hardware, this is creating a pull for the design of responsive and agile next generation technologies that can provide rapid, flexible and multifunctional devices.To realise electronic functionality, voltages are used to control the electrical properties of materials, changing the conductivity of a channel to create transistors, diodes, memory elements and more, with the function tied to the device geometry. The performance of the electrical device depends on both the material used for the conducting channel and the way the voltage is coupled to it. Similar devices are also used to probe the fundamental Physics of electronic interactions in materials, where a voltage can be used to control the number of charge carriers in the material in order to study the effect of interactions between them. These interactions can lead to novel phases, such as unconventional superconductivity or reversible transitions from metallic to insulating behaviour, that offer new opportunities for advanced electronics. The functionality of the devices is thus tied to the design and integration of advanced functional materials to engender the optimal physical properties to the conducting channel and its most efficient coupling to the applied control voltage. For the conducting channel, two-dimensional materials (2DMs) are one of the most exciting areas of research and are an area in which the UK is truly world-leading. There are now large and diverse families of 2DMs, with metallic, semiconducting, insulating, magnetic, superconducting and more properties. As they are atomically thin, the external voltage effects all of the atoms in the 2DM equally, giving more defined control over the conductivity than in conventional three-dimensional materials. Coupling to external voltages, with spatial control over the pattern of applied voltages, can be used to create highly efficient light-emitting diodes, transistors, and memory elements. What is achievable is usually limited by the coupling to the external voltage.Ferroelectrics offer the potential to dynamically control this coupling, with nanoscale spatial resolution and fast switching. A ferroelectric has a spontaneous polarisation, with a large net surface charge, organised in nanoscale domains of positive or of negative surface charge. If a 2DM is placed on a ferroelectric, with a clean interface between them, this surface charge can dramatically alter the electronic properties of the 2DM by changing the number of charge carriers in the 2DM. By dynamically controlling the domain structure in the ferroelectric, fast and agile 2D electronics can be formed. Unfortunately, although proof-of-principle devices have been made, efficient coupling between ferroelectrics and 2DM has not yet been achieved.Our team is uniquely suited to address this challenge, developing optimised processes for integrating 2DMs and ferroelectrics and demonstrating new agile electronics based on moving and switching the domains in the ferroelectric. By doing this, we will bring together two important fields, taking the potential of each to create a new area that will give new opportunities for probing fundamental Physics and developing new electronics.