High Efficiency UV-LEDs Based on Hybrid 2D/3D Materials

铝-镓-铟-氮化物材料体系制造了非常有效的可见光发射器，但仍然是低效的紫外线发射器。因此，不断增加的紫外线发射器在医疗保健、个人卫生和国土安全方面的应用继续由笨重、低效和有毒的传统光源来满足。该项目将采用一种新的方法；它将结合基于铝-镓-铟-氮化物的三维(3D)材料和基于氮化硼的二维(2D)材料来创造新的混合材料。这些混合材料有望减少内部光发射损失，以产生比目前最先进的紫外线发射器效率高三倍以上的紫外线发射器。拟议的研究应该可以用更高效、更小、更安全和更经济的发射器来取代传统的发射器。该项目还将培训研究生，以保持美国在这项技术方面的领先地位，它将鼓励少数族裔学生从事科学教育，并将引起本科生和公众对半导体研究的兴趣。技术描述：在UV-C范围(280 nm-220 nm)发射的紫外光发光二极管(UV-LED)被广泛需要，但效率非常低。这项拟议研究的科学目标是通过研究将新材料集成到LED结构中来创造下一代垂直导电设备，从而提高280 nm波长的UV-LED的效率。在过去的二十年里，UV-LED的研究重点主要集中在改善材料质量，以提高外量子效率(EQE)。EQE是内量子效率(IQE)、注入效率(IE)和光提取效率(Lee)的乘积。在典型的280 nm UV-LED中，IQE和IE约为80%，而Lee小于5%，导致EQE小于4%。拟议的项目旨在通过在UV-LED结构中加入2D和3D材料的混合来增加LEE，以减少内部吸收和反射。仿真结果表明，该方案可以显著提高系统的LEE，达到48%左右。因此，相对于最先进的280 nm UVLED发射器的平均EQE(~10%)，它应该会将EQE提高三倍以上。这个项目的成功将使这项技术实现飞跃。该项目包括金属-有机化学沉积(MOCVD)外延生长、器件设计、工艺和材料/器件表征；它将增进我们在这些领域的理解和熟练程度。参与该项目的研究生和本科生将成为这些技术方面的专家，因为他们将成为下一代研究人员。该项目由电气、通信和网络系统部门(ECCS)和既定的激励竞争研究计划(EPSCoR)联合资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The material system of aluminum-gallium-indium-nitride makes very efficient visible light emitters but still inefficient ultraviolet emitters. As a result, the ever-increasing applications of ultraviolet light emitters in healthcare, personal hygiene, and homeland security continue to be fulfilled by conventional sources that are bulky, inefficient, and toxic. This project will take a new approach; it will combine 3-dimensional (3D) materials based on aluminum-gallium-indium-nitride with 2-dimensional (2D) materials based on boron-nitride to create new hybrid materials. These hybrid materials are expected to reduce internal light emission losses to yield ultraviolet emitters that are more than three times more efficient than the current state-of-the-art. The proposed research should make it possible to replace conventional emitters with the more efficient, smaller, safer, and more economical emitter. The project will also train graduate students in order to retain US leadership in this technology, it will seek to encourage minority students to pursue science education, and it will generate interest in semiconductor research among undergraduate students and the public.Technical Description: Ultraviolet light-emitting diodes (UV-LEDs) emitting in the UV-C range (280nm – 220 nm) are widely needed but highly inefficient. The scientific objective of the proposed research is to increase the efficiency of UV-LEDs emitting at 280 nm wavelength by investigating the integration of new materials into LED structures to create the next generation of vertically conducting devices. For the last two decades, the focus of UV-LED research was mainly to improve the material quality with an aim to increase the external quantum efficiency (EQE). The EQE is the product of internal quantum efficiency (IQE), injection efficiency (IE), and light extraction efficiency (LEE). In a typical 280 nm UV-LED, the IQE and IE are around 80%, whereas the LEE is less than 5% resulting in EQE less than 4%. The proposed project aims to increase LEE by incorporating hybrids of 2D and 3D materials into the UV-LED structures so as to reduce internal absorptions and reflections. Simulations project that the proposed scheme will dramatically improve the LEE to around 48%. Thus, it should increase the EQE by more than three times relative to the average EQE (~ 10%) of state-of-the-art 280 nm UVLED emitters. Success in this project will leap the technology forward. The project entails epitaxial growth by metal-organic chemical deposition (MOCVD), device design, processing, and material/device characterizations; it will enhance our understanding and proficiency in these fields. The graduate and undergraduate students involved in the project will become experts in these techniques as they become the next generation of researchers.This project is jointly funded by the division of Electrical, Communications and Cyber Systems (ECCS), and by the Established Program to Stimulate Competitive Research (EPSCoR).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.