Strain Effects in Transition Metal Dichalcogenide Field-Effect Transistors

职务名称：单层过渡金属二硫族化物场效应晶体管中的应变效应应变是电子器件设计和性能的重要变量。它不仅在推动硅技术发展方面发挥了核心作用，而且还在继续推动全新类型的设备，如应变电子学和电子皮肤。与体半导体相比，单层过渡金属二硫属化物（TMD）由于其原子厚度而具有相当丰富的应变关系。这不仅允许这些材料获得微加工Si不可能的变形，而且还导致应变成为许多常见器件处理步骤的无意伪影。该项目将研究应变对具有单层TMD沟道的场效应晶体管（FET）的影响，这可以提高这些器件的性能极限，并解决与有害应变相关的主要集成和可靠性挑战。从这个项目中提炼出来的知识将通过位于研究者大学的教育中心卡鲁斯工程教育学院（CIEE）支持该地区的K-12科学，技术，工程和数学（STEM）课程。这包括在CIEE举办的暑期校园实践活动的开发，以及为该地区的学区制定与STEM相关的课程计划，以促进工程的多样性。该项目的目标是严格调查单层TMD及其接触点中应变对低场和高场传输的影响。所提出的研究有可能在电子器件领域发生变革，因为应变可以显著地调制能带结构，在低场传输中驱动记录压阻效应，并在高场传输中调谐饱和速度。此外，关于接触处应变影响的新的定量知识可以推进诸如柔性设备之类的技术，其中接触失效通常是凭经验描述的。除了均匀的应变，短程应变波动对运输的影响将被表征，并适合新开发的运输模型。器件将在具有不同沟道长度的柔性基板上制造，这允许沟道和接触的解耦。将使用机械变形赋予应变，并使用拉曼光谱和光致发光表征应变。电特性将适合于低场（玻尔兹曼输运方程）和高场（多路蒙特卡罗）输运模型，占几个散射机制。这包括声子，中性和电荷缺陷，以及一些第一个模型的发展，以考虑短程应变变化。该项目产生的所有知识将通过出版物和研究者课程的内容传播，以达到尽可能广泛的受众。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Title: Strain Effects in Monolayer Transition Metal Dichalcogenide Field-Effect TransistorsStrain is a powerful variable in the design and performance of electron devices. Not only has it played a central role in boosting Si technology, but it continues to enable entirely new types of devices like straintronics and electronic skins. In comparison to bulk semiconductors, monolayer transition metal dichalcogenides (TMDs) have considerably richer relationships with strain due to their atomic thickness. This not only allows these materials to access deformations not possible with micromachined Si, but also results in strain being an unintentional artifact of many common device processing steps. This project will investigate the effects of strain on field-effect transistors (FETs) with monolayer TMD channels, which can advance the performance limits of these devices and solve major integration and reliability challenges associated with deleterious strain. Knowledge distilled from this project will support K-12 science, technology, engineering, and mathematics (STEM) programs in the region through the Caruth Institute for Engineering Education (CIEE), an educational center located at the investigator's university. This includes the development of hands-on summer campus hosted at CIEE, and the development of STEM-related lesson plans for school districts around the region that promote diversity in engineering.The goal of this project is to provide a rigorous investigation of the effect of strain on the low-field and high-field transport in monolayer TMDs and at their contacts. The proposed research has potential to be transformative in the field of electronic devices as strain can dramatically modulate the band structure, driving record piezoresistive effects in the low-field transport and tuning saturation velocity in the high-field transport. Furthermore, new quantitate knowledge on the effects of strain at contacts can advance technologies such as flexible devices, where contact failure is often described empirically. In addition to the uniform strain, the effects of short-range strain fluctuations on the transport will be characterized and fit to newly developed transport models. Devices will be fabricated on flexible substrates with varying channel lengths, which allows for a decoupling of the channel and contacts. Strain will be imparted using mechanical deformations, and characterized using Raman spectroscopy and photoluminescence. Electrical characterizations will be fit to low-field (Boltzmann Transport Equation) and high-field (multivalley Monte Carlo) transport models that account for several scattering mechanisms. This includes phonons, neutral and charge defects, and the development of some of the first models to account for short-range strain variation. All knowledge generated by this project will be disseminated through publications and inclusions in the investigator's courses to reach the broadest possible audience.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.