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持续增加，为这些设备供电的能源需求也在增加；因此，计算能力需求的降低可能会对全球能源消耗产生重大影响。在这项研究中，人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，目标是降低运行功率。具体地说，一种新型的聚合物电解质(即离子导电聚合物)被设计成在施加电场时在二维(2D)半导体中诱导应变。2D半导体的厚度只有一个分子。应变改变了2D半导体的电学性质，然后可以被检测到以执行逻辑运算。据预测，这种变化发生在比传统晶体管中使用的电压更低的电压下，因此操作该设备所需的功率更低。除了在纳米电子学中的应用外，这项研究还为相变设备开发了新的材料，这些设备对电、化学或应变刺激做出反应，在脑启发计算和人工突触方面具有潜在的应用。从事这一项目的博士后学者、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、无机材料科学和设备物理，目标是制造低功率晶体管。研究部分提供课堂上使用的教育案例研究，以及博士后、研究生和本科生的跨学科培训。技术描述：一种使2D晶体应变的新方法正在探索中，该方法使用场效应晶体管(FET)和悬挂的MoTe2沟道，其中栅氧化物被定制合成的离聚体(即单离子导体)所取代。栅极偏压导致离聚体中的静电不平衡，从而使2D晶体应变，并导致半导体向金属相变。相变是通过FET的电流-电压特性检测到的，预计将在亚伏栅极偏置下发生，开关时间为纳秒。这种方法提供了一种与传统的CMOS结构类似的门控制结构，但采用了新的材料和新的物理。这项研究既解决了动态控制2D晶体相行为的基本问题，也解决了实际问题。基本的挑战是在2D晶体中实现足够大的应变来诱导相变；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能够利用这种相变特性的电子设备，用于低功率晶体管、大脑启发的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.