Polarization-Driven Electron-Hole Bilayers in Quantum Wells

非技术描述：该项目旨在发现隐藏在材料系统中的新的电子和光学现象，该材料系统目前用于固态照明，通信系统和电力电子，以及几乎所有的iphone和ipad。研究的重点是氮化镓量子结构中相互靠近的相反符号的载流子。相反符号的载体保持各自的身份，直到它们收到一个命令（例如通过一个小电压或电流），在此基础上它们强烈混合，要么发光，要么以电流的形式流动，能量消耗很少。这种现象长期以来一直被期望用于制造低功耗或超快和节能的电子开关，用于光子器件，以及潜在的传感器环境。因此，该项目的研究结果有可能影响电子和光电子工业以及环境健康和安全系统。该项目在物理学、材料科学和电气工程交叉的一个迷人的新兴领域培养研究生。除了扩大现有的外展项目外，还考虑开展新的活动，特别关注高中生和代表性不足的群体，包括直接参观学校和课堂演示。在期刊出版物中传播研究成果，在会议上发表演讲，并将其纳入PI在线提供的课程，确保了尽可能广泛的受众。技术描述：本项目探索iii -氮化物量子结构的量子输运和光学性质及其在大极化场驱动下的电子-空穴双层体系中的潜在应用。由于缺乏极化、掺杂限制或击穿场低，在其他材料体系中很难产生这样的双分子层。当创建时（例如，在二维层状材料中），会出现与化学掺杂和接触可靠性相关的额外挑战。在这个项目中，PI利用了最近独特的技术进步，在AlN衬底上的新型压缩应变GaN量子阱中，外延再生接触到二维电子和空穴气体，在一个全新的平台上探索双层物理。平行的二维电子和空穴系统在几个复杂的层次上拥有丰富的物理学——从可以导致新的电子和光子器件的非耦合二维电子-气体/二维空穴气体p-n二极管，到表现出库仑阻力的弱耦合系统，再到表现出激子或玻色-爱因斯坦凝聚的强耦合系统。由于极化驱动拓扑边缘态的诱人可能性，该项目的成果具有在超低功耗电子、光子量子信息处理应用方面取得重大科学和技术进步的潜力。

Non-technical description: This project aims to discover new electronic and optical phenomena hidden in a material system that is currently used in solid state lighting, in communication systems, and power electronics, and is in almost all iPhones and iPads. The research focuses on electrical charge carriers of opposite signs located very close to each other in gallium nitride quantum structures. The carriers of opposite signs maintain separate identities, until they receive a command (for example through a small voltage or a current), upon which they mix strongly to either emit light, or flow as currents with very little energy dissipation. This sort of phenomena has been long desired for making low-power or ultrafast and energy-efficient electronic switches, for photonic devices, and potentially for sensor environments. Thus, findings of this project have a potential to impact the electronics and photonics industries, and environmental health and safety systems. The project trains graduate students in a fascinating emerging field at the intersection of physics, materials science, and electrical engineering. In addition to expanding existing outreach programs, new activities are considered with a special focus on the high-school students and underrepresented groups, including direct school visits and in-class demonstrations. The dissemination of research results in journal publications, presentations at conferences and inclusion in courses taught by the PI made available online ensures the outreach to the widest possible audience.Technical description: This project explores the quantum transport and optical properties of III-nitride quantum structures and their potential applications in electron-hole bilayer systems, driven by large polarization fields. Such bilayers are difficult to create in other material systems either because of the lack of polarization, doping limitations, or because of low breakdown fields. When created (for example, in two-dimensional layered materials), additional challenges occur related to their chemical doping and contact reliability. In this project, the PI takes advantage of unique recent technological progress in epitaxially regrown contacts to two-dimensional electron and hole gases in novel compressively strained GaN quantum wells on AlN substrates to explore bilayer physics in a fundamentally new platform. Parallel two-dimensional systems of electrons and holes boast rich physics at several levels of complexity - from uncoupled two-dimensional electron-gas / two-dimensional hole gas p-n diodes that could lead to new electronic and photonic devices, to weakly coupled systems, exhibiting Coulomb drag, to strongly coupled systems that have shown glimpses of excitonic or Bose-Einstein condensation. And with the tantalizing possibility of polarization-driven topological edge states, the outcomes of the project has a potential for significant scientific and technological advances for ultra-low power electronic, photonic quantum information-processing applications.