CAREER: Towards highly efficient UV emitters with lattice engineered substrates

本CAREER项目的目标是显著提高紫外线范围内发光二极管的效率，特别是在现有方法显示效率突然下降的范围内。将使用一种新型柔性材料，这将有助于改善这类紫外线发射器面临的应变相关问题，并且这些材料还将在特定方向上引导光线，以有效地从设备中提取光线。实验和理论研究的结合将用于演示光提取，材料和设备级别的改进，所有这些都比当前解决方案提高了10倍。开发的结构不仅将提高现有产品的性能，而且还将在医学领域实现全新的应用-皮肤病治疗和心血管/眼科手术，农业-食品储存和养殖，卫生处理-空气，地表水和水；通过高效设备节省能源，从而实现可持续性，并最终提高银行和身份证安全系统的可靠性。更广泛的影响活动将涉及评估拟议的研究和大规模采用紫外线发射器取代现有汞灯对生物多样性、医学和粮食安全等各个领域的影响。利用教师项目的研究经验，在教育系统早期介绍半导体及其社会影响，建议在高中课程中加入“半导体是有趣的”模块。由于鼓励CHIPS法案相关举措，提出了不同层次的不同类型的劳动力培训-大学预科，本科和研究生水平，以填补国家层面的劳动力短缺需求。计划与农业社区开展社区参与活动，以提高人们对紫外线发射器的认识，以及它们如何能够加强国家粮食安全。技术描述：本CAREER项目旨在解决III-氮化物固体发射器在280-365 nm紫外发射波长范围内的外量子效率差距，从而实现高功率紫外发光二极管的新体制。在这个波长范围内，器件的效率对波长有明显的依赖性，这将被提出的解决方案解耦。研究方法将涉及基于多孔半导体的机械柔性和反射衬底的开发，以重新定义用于设计iii族氮化物基器件外延结构的关键厚度指标，以实现预期效率提高一个数量级。利用新的量子阱和载流子注入层，将采用新的方法合成多孔材料，并实现半导体反射器。将开发机械、光学和光电计算模型来指导实验探索，并增强对所使用的外延结构的力学和物理的理解。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。

The objective of this CAREER project is to significantly improve the efficiency of light emitting diodes in the ultraviolet range, especially in those ranges where incumbent methods show an abrupt drop in efficiency. A new class of flexible materials will be used that will help improve strain related issues faced by this class of ultraviolet emitters, and these materials will also direct light in a specific direction to efficiently extract light out of the device. A combination of experimental and theoretical investigations will be employed to demonstrate light extraction, material, and device level improvements all resulting in up to 10x improvement over current solutions. The developed structures will not only enhance the capabilities of currently available products but will also enable completely new applications in the field of medical science – skin disease treatments and cardiovascular/eye surgeries, agriculture – food storage and farming, sanitization- air, surface and water; energy savings from efficient devices resulting in sustainability and finally improve reliability of security systems used in banks and for ID cards. The broader impacts activities will involve assessing the impact of proposed research and large-scale adoption of ultraviolet emitters over incumbent mercury lamps on various fields such as biodiversity, medicine and food security. Incorporation of a module on ”semiconductors are fun” in high school curriculum is proposed by leveraging the research experience for teachers program to introduce semiconductors and their societal impacts early on in the education system. Different kinds of workforce trainings at various levels – precollege, undergraduate and graduate level are proposed to fill the national level workforce shortage demand owing to the encouraging CHIPS Act related initiatives. Community engagement activities are planned with farming communities to generate awareness about ultraviolet emitters and how they can enhance national food security.Technical description: This CAREER project aims to address the gap in external quantum efficiency of III- nitride solid state emitters in the ultraviolet emission wavelength range of 280-365 nm to enable a new regime of high-power ultraviolet light emitting diodes. There is a sharp wavelength dependence on the efficiency of devices in this wavelength range, that will be decoupled by the proposed solution. The research approach will involve the development of mechanically compliant and reflective substrates based on porous semiconductors, to redefine the critical thickness metrics used to design group III-nitride based device epitaxial structures to achieve a projected efficiency improvement by an order of magnitude. Using novel quantum well and carrier injection layers, new methods of synthesis of porous materials, and implementation of semiconductor reflectors will be employed. Mechanical, optical and opto-electrical computational models will be developed to guide experimental explorations and enhance the understanding of the mechanics and physics of the epitaxial structures being used.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.