All-Semiconductor Enhanced Efficiency Plasmonic Mid-IR Emitters

半导体光源，特别是激光器和发光二极管（led），在过去的五十年中，已经成为许多最重要的技术进步的驱动力。从我们通信网络中使用的电信激光器，到固态照明应用中降低能耗的led，半导体为广泛的技术进步提供了紧凑，低成本和高效的光源。然而，上述来源和应用的大多数是在电磁波谱的可见和近红外部分。除了少数例外，波长较长的中红外（中红外）缺乏同等效用和效率的半导体光源，尽管波长范围对生物医学，环境，工业以及安全和国防应用具有重要的技术意义。该波长范围内半导体源的缺乏主要归因于中红外光电材料固有的低效率，其以热的形式比以光的形式更有效地耗散能量。然而，中红外发射器固有的低效率为实施这些长波长独特的效率增强新方法提供了非常现实的机会。该项目旨在通过结合外延材料生长，光-物质相互作用和半导体器件架构的最新进展来改变中红外半导体光源领域，以开发一类高效的半导体中红外光源，具有红外量子通信，红外传感，热信号和生物医学成像的潜在应用。我们的技术努力将通过强有力的K-12外展计划以及持续的REU和RET指导得到加强。技术：等离子体领域承诺在光学和光电子学方面取得广泛的变革性进展，包括但不限于片上亚衍射极限波导，更高效率的光伏，亚衍射极限和超高效发射器，以及增强灵敏度的传感器系统。上述研究工作主要集中在电磁波谱的近红外和可见波长（400 nm - 3um），其中高效发射器大量存在，等离子体材料的引入通常会导致发射效率降低（即使其他好处，如亚波长限制，也被证明）。另一方面，中红外（3 - 30um）是一个基本上没有有效发射器的波长范围，在这个波长范围内，等离子体可以用来提高而不是降低发射器的效率。中红外也是高质量等离子体材料、量子工程和纳米结构发射体可以在同一材料体系中外延生长的波长范围。该项目将利用高掺杂半导体“金属”平台，结合量子工程有源区域和图片化外延生长，在单片半导体平台中开发新的，提高效率的中红外源。该项目将为量子工程发射体和设计等离子体结构之间的光-物质相互作用的基础研究提供转型机会。与此同时，该项目将展示等离子体可以用来实现中红外源效率的显著提高。该项目的最终目标是演示第一个用于高效中红外发光器件的电驱动全半导体等离子体/量子发射源，并随后将其集成到中红外光学系统中。这些pi在与奥斯汀更大的社区进行接触方面有着良好的记录，作为拟议努力的一部分，他们将通过定期在K-12教室进行接触和模块化活动来加强这些联系。pi致力于其研究小组的多样性，并将以此多样性为基础，招募有才华和多样化的学生群体参与该项目，这将使参与的学生接触到晶体生长、光学、器件设计、材料和器件特性方面的前沿研究。pi将通过德州大学现有的夏季REU和RET项目为本科生和当地K12教师提供建议。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。

Semiconductor light emitters, particularly lasers and light emitting diodes (LEDs), have served as the driving force for many of the most significant advances in technology over the past five decades. From the telecom lasers used in our communications networks, to the LEDs reducing energy consumption in solid state lighting applications, semiconductors offer compact, low cost, and efficient light sources for a broad range of technological advances. However, the majority of the aforementioned sources and applications lie in the visible and near-infrared portions of the electromagnetic spectrum. With a few exceptions, the longer wavelength mid-infrared (mid-IR) lacks semiconductor-based light sources of equivalent utility and efficiency, despite being a wavelength range of significant technological importance for a range of biomedical, environmental, industrial, as well as security and defense, applications. The lack of semiconductor sources in this wavelength range can largely be attributed to the intrinsic inefficiency of mid-IR optoelectronic materials, which dissipate energy more efficiently as heat than as light. The inherent inefficiency of mid-IR emitters, however, offers very real opportunities for implementing new approaches for efficiency enhancement unique to these long wavelengths. This project seeks to transform the field of mid-IR semiconductor light emitters by marrying recent advances in epitaxial materials growth, light-matter interactions, and semiconductor device architectures to develop a class of efficient semiconductor mid-IR light sources, with potential applications in infrared quantum communications, infrared sensing, thermal signaling, and biomedical imaging. Our technical efforts will be augmented by a robust K-12 outreach program, as well as sustained REU and RET mentoring.Technical: The field of plasmonics has promised a broad range of transformational advances in optics and optoelectronics, including but not limited to, on-chip sub-diffraction limited waveguiding, higher efficiency photovoltaics, sub-diffraction limit and ultra-efficient emitters, and enhanced sensitivity sensor systems. Research efforts on the above have largely focused on the near-infrared and visible wavelengths of the electromagnetic spectrum (400 nm - 3um), where efficient emitters abound, and the introduction of plasmonic materials generally results in decreased emission efficiency (even if other benefits, such as sub-wavelength confinement, are demonstrated). The mid-IR (3 - 30 um), on the other hand, is a wavelength range largely devoid of efficient emitters, where plasmonics can be leveraged to improve, not degrade, emitter efficiency. The mid-IR is also a wavelength range where high quality plasmonic materials and quantum engineered and nanostructured emitters can be grown epitaxially in the same material system. This project will utilize the highly-doped semiconductor 'metals' platform, combined with quantum engineered active regions and patterned epitaxial growth, to develop new, increased efficiency, mid-IR sources in a monolithic semiconductor platform. The project will offer transformational opportunities for fundamental investigation of light-matter interactions between quantum engineered emitters and designer plasmonic structures. At the same time, the project will look to demonstrate that plasmonics can be leveraged to realize significant improvements in mid-IR source efficiency. The ultimate goal of the project is the demonstration of the first electrically-driven all-semiconductor plasmonic/quantum-emitter sources for efficient mid-IR light emitting devices and their subsequent integration into mid-IR optical systems.The PIs have strong track records of outreach to the larger Austin community, and as part of the proposed effort will strengthen these ties with regular outreach and modular activities in K-12 classrooms. The PIs have a commitment to diversity in their research groups, and will build off of this diversity and look to recruit a talented and diverse group of students to the project, which will expose participating students to cutting edge research in crystal growth, optics, device design and materials and device characterization. The PIs will advise undergraduate students and local K12 teachers through existing summer REU and RET programs at UT.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.