Polarization-Driven Electron-Hole Bilayers in Quantum Wells

非技术描述：该项目旨在发现隐藏在一种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设备，几乎所有iPhone和iPad都使用这种材料系统。这项研究集中在氮化镓量子结构中符号相反的电荷载流子之间的位置非常接近。相反标志的载体保持不同的身份，直到它们接收到命令(例如通过小电压或电流)，它们强烈混合以发出光，或以电流的形式流动，能量消耗非常小。这种现象长期以来一直被用于制造低功率或超快和节能的电子开关，用于光子设备，并可能用于传感器环境。因此，该项目的发现有可能对电子和光电子行业以及环境健康和安全系统产生影响。该项目在一个迷人的新兴领域培养研究生，该领域是物理学、材料科学和电气工程的交汇点。除了扩大现有的外展方案外，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，包括直接学校访问和课堂示范。研究成果在期刊出版物上的传播、在会议上的演讲和在PI讲授的课程中的在线提供确保了对尽可能广泛的受众的推广。技术描述：这个项目探索了III-氮化物量子结构的量子输运和光学性质，以及它们在大偏振场驱动的电子-空穴双层系统中的潜在应用。由于缺乏极化、掺杂限制，或者因为击穿电场较低，在其他材料系统中很难形成这样的双层膜。在制造时(例如，在二维层状材料中)，会出现与其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AlN衬底上新型压缩应变GaN量子阱中与二维电子和空穴气体的外延再生接触的独特最新技术进步，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不同的复杂程度上拥有丰富的物理学--从可能导致新的电子和光子设备的未耦合的二维电子气体/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，再到显示出激子或玻色-爱因斯坦凝聚的强耦合系统。由于偏振驱动的拓扑边缘状态具有诱人的可能性，该项目的成果有可能在超低功率电子、光子量子信息处理应用中取得重大科学和技术进步。

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.