A New Approach to Explore the Semiconductor-to-Metal Phase Transition in Two-Dimensional Crystals Using Ionomers

非技术描述：随着电子设备数量的不断增加，为这些设备供电的能源需求也在不断增加；因此，降低计算能力需求可能会显著影响全球能源消耗。在这项研究中，我们正在探索一种基于新材料的新器件概念，以取代传统的硅基晶体管，目标是降低工作功率。具体而言，设计了一种新型聚合物电解质（即离子导电聚合物），当施加电场时，它可以在二维（2D）半导体中诱导应变。二维半导体的厚度只有一个分子。应变改变了二维半导体的电学特性，然后可以感应到它来执行逻辑运算。预计这种变化将在比传统晶体管更低的电压下发生，因此操作该器件所需的功率更低。除了在纳米电子学方面的应用之外，这项研究还为响应电、化学或应变刺激的相变器件提供了新的材料，在脑启发计算和人工突触方面具有潜在的应用前景。从事该项目的博士后学者、研究生和本科生将受益于一个跨学科项目，该项目结合了化学、聚合物科学、无机材料科学和器件物理学，目标是设计低功耗晶体管。研究部分提供用于课堂的教育案例研究，以及博士后、研究生和本科生的跨学科培训。技术描述：一种应变2D晶体的新方法正在探索使用具有悬浮MoTe2通道的场效应晶体管（FET），其中栅极氧化物由定制合成的离子聚合物（即单离子导体）取代。栅极偏压在离子中引起静电不平衡，使二维晶体应变并引起半导体到金属的相变。相变是通过FET的电流-电压特性检测到的，并且预计会在亚伏栅极偏置下以纳秒的开关时间发生。这种方法提供了一种类似于传统CMOS结构的栅极控制体系结构，但采用了新材料和新物理。该研究解决了动态控制二维晶体相行为的基础和实际挑战。最根本的挑战是在二维晶体中实现足够大的应变，以诱导相变；在这里，通过离子的静电控制被用来解决这一挑战。实际的挑战是制造一种电子设备，可以利用这种相变特性用于低功耗晶体管、大脑启发计算或人工突触的开发。

Non-technical description: As the number of electronic devices continues to increase, so does the need for energy to power these devices; therefore, decreasing computing power requirements could significantly impact global energy consumption. In this study, a novel device concept based on new materials is being explored to replace traditional silicon-based transistors, with the goal of lowering the operating power. Specifically, a new type of polymer electrolyte (i.e., ion conducting polymer) is designed to induce strain in a two-dimensional (2D) semiconductor when an electric field is applied. The 2D semiconductor has a thickness of only one molecule. The strain changes the electrical properties of the 2D semiconductor, which can then be sensed to perform logic operations. The change is predicted to occur at voltages lower than ones used in conventional transistors, and therefore the power required to operate the device is lower. In addition to applications in nanoelectronics, this research advances new materials for phase change devices that respond to electrical, chemical or strain stimuli, with potential application in brain-inspired computing, and artificial synapses. The postdoctoral scholar, graduate and undergraduate students who work on this project benefit from an interdisciplinary project that combines chemistry, polymer science, inorganic materials science and device physics with the goal of engineering low-power transistors. The research component provides educational case studies to be used in the classroom, and interdisciplinary training of postdocs, graduate and undergraduate students. Technical Description: A new approach to strain 2D crystals is being explored using a field-effect transistor (FET) with a suspended MoTe2 channel for which the gate oxide is replaced by a custom-synthesized ionomer (i.e., single-ion conductor). Gate bias induces an electrostatic imbalance in the ionomer that strains the 2D crystal and induces a semiconducting to metallic phase change. The phase change is detected by the current-voltage characteristics of the FET, and is expected to occur at sub-volt gate bias with nanosecond switching times. This approach offers a gate control architecture that is similar to conventional CMOS architecture but with new materials and new physics. The research addresses both a fundamental and a practical challenge for dynamically controlling the phase behavior of 2D crystals. The fundamental challenge is achieving strain in 2D crystals that is sufficiently large to induce the phase transition; here, electrostatic control via ions is used to address this challenge. The practical challenge is building an electronic device that can exploit this phase-change property for low-power transistors, brain-inspired computing, or the development of artificial synapses.