Collaborative Research: Harnessing Crystalline Phase Transition in 2D Materials for Ultra-Low-Power and Flexible Electronics

可穿戴电子和移动设备技术的快速发展使得探索和展示具有超低功耗、快速、小尺寸和灵活机械性能的新型半导体器件变得至关重要和迫切。原子层半导体及其从块状、层状过渡金属二卤化物晶体中分离出来的二维纳米结构，由于其非传统和特殊的电学、光学和机械性能，在纳米电子学、纳米光子学和纳米机电系统中具有广泛的应用前景。在某些原子层半导体材料中发生的受控晶体相变及其伴随的半导体到金属的相变，最终可能导致重要的设备和电路应用，从而允许以超低功耗进行先进的计算、存储和传感。该项目结合了实验、理论和模拟方法，探索、建模和演示了一种基于原子层半导体中受控晶体相变机制的新型原子薄、机械灵活的电子设备。基于原子薄半导体材料相变的器件具有超低功耗和机械柔性的特性，使其在未来的柔性电子、物联网和计算机技术中具有吸引力。在这个项目中，私人投资机构将开发和传播课程模块和模拟工具，并及时利用研究活动，从西部储备大学和佛罗里达大学招募和扩大从高中到研究生水平的代表性不足学生的参与。这一合作研究项目的目标是为理解和获取用于超低功率开关器件和灵活电子应用的二维过渡金属双卤化物材料的栅极电压和应变控制晶体相变奠定必要的知识库，并为其铺平道路。拟议的研究活动包括：(1)开发一个计算高效和物理上有意义的多尺度模拟平台来模拟过渡金属二卤化物晶体中由栅极电压或应变引起的晶体相变现象；(2)通过实验探索应变和栅压诱导过渡金属二卤化物材料中的相变；(3)将过渡金属二卤化物器件中晶体相变的实验表征与开发相变柔性电子器件和开关器件的理论工作相结合；(4)在合理设计的器件平台上设计相变开关机制，以实现陡峭的亚阈值斜率和超低功率逻辑开关。这个实验-理论合作团队将使用先进的纳米器件制造、表征、建模和模拟技术来探索和了解过渡金属二卤化物材料的相变如何被定制、控制和用于超低功率和灵活的电子应用。这项研究将加深对原子层半导体相变现象的基本了解，并开发有前途的器件概念和模型，以利用原子薄层半导体中的栅极电压和应变控制的晶体相变，使未来的器件和系统能够用于计算、传感和通信。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Rapid advances in wearable electronics and mobile device technologies have made it crucial and imperative to explore and demonstrate new semiconductor devices with ultralow-power, fast speed, small size, and flexible mechanical properties. Atomic layer semiconductors and their two-dimensional nanostructures isolated from bulk, layered transition metal dichalcogenide crystals are promising for many applications in nanoelectronics, nanophotonics, and nanoelectromechanical systems, due to their unconventional and exceptional electrical, optical and mechanical properties. Controlled crystalline phase transition, which occurs in certain atomic layer semiconductor materials, and its accompanying semiconductor-to-metal transition, have the potential to eventually lead to important device and circuit applications that permit advanced computing, memory, and sensing with ultralow power consumption. This project combines experimental, theoretical, and simulation approaches to explore, model, and demonstrate a new class of atomically thin, mechanically flexible electronic devices based on the mechanisms of controlled crystalline phase transition in atomic layer semiconductors. The ultralow power and mechanical flexible properties of the devices based on phase transition in atomically thin semiconductors materials make them attractive in future flexible electronics, internet-of-things, and computer technologies. In this project, the PIs will develop and disseminate course modules and simulation tools, and timely employ the research activities to recruit and broaden participation from underrepresented students from high school to graduate student levels, at both Case Western Reserve University and University of Florida. The goals of this collaborative research project are to develop the essential knowledge base for, and to pave the way toward, understanding and harvesting gate-voltage and strain-controlled crystalline phase transition in two-dimensional transition metal dichalcogenide materials for ultralow-power switching devices and flexible electronics applications. The proposed research activities include: (i) Develop a computationally efficient and physically meaningful multiscale simulation platform to simulate crystalline phase transition phenomena in transition metal dichalcogenide crystals induced by a gate voltage or strain; (ii) Experimentally explore strain and gate-voltage-induced phase transition in transition metal dichalcogenide materials; (iii) Couple experimental characterization of the crystalline phase transition in transition metal dichalcogenide devices with theoretical work to develop phase transition flexible electronics and switching devices; (iv) Engineer the phase-transition switch mechanisms in rationally designed device platforms, to achieve steep sub-threshold slope and ultralow-power logic switches. This experiment-theory collaborative team will use advanced nanodevice fabrication, characterization, modeling and simulation techniques to explore and understand how phase transition in transition metal dichalcogenide materials can be tailored, controlled, and utilized for ultralow power and flexible electronics applications. The study will deepen fundamental understanding of phase change phenomena in atomic layer semiconductors, and develop promising device concepts and models to harness gate-voltage and strain-controlled crystalline phase transition in atomically thin semiconductors, to enable future devices and systems for computing, sensing, and communication.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.