EAGER: Flexible III-N High-Electron-Mobility Transistors with Controlled External Bending Strains for Wide-Bandgap Semiconductor Devices

iii族氮化物（III-N）半导体作为节能环保的光源，被2014年诺贝尔物理学奖所认可，为人类带来了巨大的利益。它们也是节能电力转换和开关、无线通信、电子战和光存储系统的重要材料。本项目拟利用设备结构的机械可弯曲性，研究已经具有高性能和高效率的设备的扩展功能和进一步增强性能。该项目预计将产生新概念器件和相关的新器件物理，以促进器件技术方面的知识。此外，这项研究的结果将提供一个潜在的颠覆性半导体平台，可以集成到其他半导体设备中，具有多功能和应用的多功能性，以实现节能和收获。新概念是在理论研究的基础上发展起来的，尚未通过工作装置的演示来证明，这是拟议项目的主要目标之一。这将对社会和经济产生重大影响，因为基于半导体的电子、光子学和能源系统是现代技术的支柱，随着电动汽车和智能电网系统的采用，这些系统在未来将变得更加重要。例如，30%的电能通过电力电子转换器，22%的总发电量用于照明，这意味着在节能和减少温室气体排放方面有望取得显着效益。与研究项目相结合的教育和推广项目将有助于传播有关绿色能源系统、可持续技术半导体设备及其社会和环境影响的知识。基于III-N异质结构的柔性器件可以利用其独特的自发极化和压电极化特性，与基于晶圆的非柔性器件相比，具有新的功能甚至进一步改善的性能特征。因此，它们为新概念器件，多功能机械-电子-光子（MEP）器件提供了机会，而不仅仅是机械柔性器件，通过主动控制具有可变外部应变的极化。该项目的目标是证明在柔性III-N结构中应用主动极化工程的概念，并为MEP器件在电子、光子和能量收集方面的应用奠定基础。基于III-N半导体的各种多功能和/或高性能MEP器件将利用柔性异质结构中的电子和光学性质与机械力之间的相互作用来开发。通过模型和实验研究，研究弯曲应变可控的柔性高电子迁移率晶体管基本特性的变化，以证明主动极化工程的概念。技术方法和任务包括：(1)不同曲率半径的器件仿真，(2)开发可弯曲器件的高保真制造工艺，(3)开发MEP器件运行的物理模型。该项目旨在生产主动极化工程电子设备和相关新设备物理的概念验证，以展示新技术平台的潜力。MEP器件提供了从根本上改变III-N半导体器件的理解和应用的潜力，从而导致新型器件和系统的创建。新的设备物理和建模结果，包括静态和动态外部应变的影响，将为这些设备的各种应用提供理论背景。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Group III-Nitride (III-N) semiconductors have brought significant benefits to mankind as energy-efficient and environment-friendly light sources, as recognized by the Nobel Prize in Physics 2014. They are also important materials for energy-efficient electric power conversion and switching, wireless communication, electronic warfare, and optical storage systems. This project proposes to study the expanded functionality and further enhanced performance of the already high-performance and high-efficiency devices using mechanical bendability of the device structure. This project is expected to produce new-concept devices and related new device physics for the advancement of knowledge in the device technology. Furthermore, the outcome of this research will provide a potentially disruptive semiconductor platform that can be integrated in other semiconductor devices with multi-functionality and application versatility for energy saving and harvesting. The new concept has been developed based on theoretical studies and has yet to be proven by the demonstration of working devices, which is one of major objectives of the proposed project. The societal and economic impacts will be significant because electronics, photonics, and energy systems based on semiconductors are the backbone of modern technology and will be even more critical in the future with the adoption of electric vehicles and smart-grid systems. As an example, 30% of electrical energy passes through power electronics converters and 22% of total generated electricity is consumed in lighting, which means that significant benefits are expected in energy saving and reduction of greenhouse-gas emission. Education and outreach programs integrated with the research program will contribute to the dissemination of knowledge on green energy systems, semiconductor devices for sustainable technology, and their societal and environmental impacts.Flexible devices based on III-N heterostructures can be equipped with new functionalities and even further improved performance characteristics compared to wafer-based non-flexible devices by exploiting their unique properties of spontaneous and piezoelectric polarizations. Therefore, they open an opportunity to new-concept devices, multi-functional mechano-electro-photonic (MEP) devices, beyond just mechanically flexible devices, by the active control of the polarizations with variable external strains. The goals of the project are to prove the concept of the active polarization engineering applied in flexible III-N structures and to lay the foundation for the MEP devices in electronic, photonic, and energy-harvesting applications. Various multi-functional and/or higher-performance MEP devices based on III-N semiconductors will be developed by utilizing the interactions between electronic and optical properties and mechanical forces in the flexible heterostructures. The changes in fundamental characteristics of flexible high-electron-mobility transistors with controlled bending strains will be investigated via both modeling and experimental studies to prove the proposed concept of active polarization engineering. Technical methods and tasks include (1) device simulation with various curvature radii, (2) the development of high-fidelity fabrication process for bendable devices, and (3) the development of a physical model for the operation of MEP devices. This project is to produce proof-of-concept actively polarization-engineered electronic devices and related new device physics to demonstrate the potential of a new technology platform. The MEP devices offer the potential to radically change the understanding and applications of III-N semiconductor devices, leading to the creation of new-type devices and systems. New device physics and modeling results including the effect of static and dynamic external strains will provide a theoretical background of such devices for various applicationsThis 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.