CAREER: Cubic Phase Green Light Emitting Diodes for Advanced Solid State Lighting

摘要标题：用于先进固态照明的立方相绿色发光二极管的研究非技术描述：该提案的研究目标是探索立方相发光二极管的基本特性，这些特性将提供缩小可见光谱中的“绿色差距”所需的关键知识，为先进的固态照明铺平道路，并连接高效照明，可靠的连接，以及通过颜色混合方法的快速联网。预计这项研究将产生重大的社会和技术影响。这项研究将通过利用六边形到立方体的相变和廉价、可扩展的硅平台，建立一种制造绿色发光二极管的新范式。由此产生的立方相GaN框架将具有许多分支，这些分支可能会影响能源、通信和医疗保健中的其他微/纳米电子光子系统。该提案计划将联合收割机技术和教育平台，包括K-12科学，技术，工程和数学教育工作，以提高美国的经济竞争力。主要研究者将开发一个基于主题的互动推广计划，“固态照明”，并将在当地少数民族入学率高（50%）的中学试点课程材料。另一个关键组成部分将是创建一个便携式展览，以启发K-12学生和公众对光和光子学的认识。所有这些材料也将在网上广泛分发。此外，纳入拟议研究结果的模块将被纳入本科和研究生课程（每年约80名学生）。此外，首席研究员将继续主办一个K-12教师和一名妇女或代表性不足的少数民族学生在研究小组每年夏天。技术说明：迄今为止，InGaN基绿色发光二极管的研究已被限制在自然发生的六角相器件的功率，效率，速度和带宽有限。这一问题推动了立方相GaN的研究发展。立方相绿色发光二极管由于0.2 eV的较低带隙而将必要的铟含量减少约10%。此外，他们可以四倍的辐射复合动力学凭借其零偏振。这项建议的智力价值源于对集成在纳米图案化互补金属氧化物半导体兼容硅上的GaN器件的分析，这将揭示立方相绿色发光二极管的特性，并提供其异质集成的变革性新知识。具体而言，立方相材料形成的结构机制将通过一系列旨在确定关键的基板纳米图案设计最大化立方相含量的实验表征技术进行研究。同时，这些（In）GaN光子结构的辐射复合动力学将被研究和它们的结构复合关系相关。这些发现将根据缺陷率（± 108 cm-2）、相含量（± 0.1%）、应力（± 0.01%）、合金含量（± 0.01%）、晶体学取向、带隙和发射能量（± 1 meV）、振动能量（± 2 cm-1）、复合动力学（± 1 ps）和空间均匀性（1.5 nm）进行定量评估。研究结果也将用于改善绿色发光二极管的辐射复合动力学，从而彻底改变GaN基光子器件的设计策略。拟议的研究将在互补金属氧化物半导体兼容的硅衬底上进行，以促进可扩展性，工业采用，并产生关于GaN-硅异质集成的新知识。所获得的知识将有助于开发新的光子器件设计，并促进对先进固态照明的更全面理解。

Abstract Title: Investigation of Cubic Phase Green Light Emitting Diodes for Advanced Solid State LightingNon-Technical Description: The research objective of this proposal is to explore the fundamental properties of cubic phase light emitting diodes that will provide the critical knowledge required to close the "green gap" in the visible spectrum paving the way towards advanced solid state lighting and bridging efficient lighting, reliable connectivity, and fast networking via color mixing approach. The proposed research is expected to have significant societal and technological impact. This research will establish a new paradigm in creating green light emitting diodes by exploiting the hexagonal-to-cubic phase transition and an inexpensive, scalable silicon platform. The resulting cubic phase GaN framework will have many ramifications that may impact other micro-/nano- electro-photonic systems in energy, communication, and healthcare. The proposal plans to combine technical and educational platforms, including K-12 Science, Technology, Engineering and Math education efforts, for increasing the economic competitiveness of the United States. The principal investigator will develop a theme-based interactive outreach program, "Solid State Lighting", and will pilot curriculum materials at local middle schools with high ( 50%) minority enrollment. Another key component will be the creation of a portable exhibit to enlighten K-12 students and the general public about light and photonics. All of these materials will also be made available online for broad distribution. Additionally, modules incorporating the findings of the proposed research will be included in undergraduate and graduate courses (~80 students annually). Furthermore, the principal investigator will continue to host one K-12 teacher and one woman or underrepresented minority student in the research group every summer.Technical Description:To date, InGaN-based green light emitting diode research has been restricted to naturally-occurring hexagonal phase devices that are limited in power, efficiency, speed, and bandwidth. This problem fueled the research for the development of cubic phase GaN. Cubic phase green light emitting diodes reduce the necessary indium content by ~10% because of a 0.2 eV lower bandgap. Also, they can quadruple radiative recombination dynamics by virtue of their zero polarization. The intellectual merit of this proposal stems from the analysis of GaN devices integrated on nano-patterned Complementary Metal-Oxide Semiconductor-compatible silicon that will shed light on the properties of cubic phase green light emitting diodes and provide transformational, new knowledge in their heterointegration. Specifically, the structural mechanisms governing cubic phase material formation will be studied through a series of experimental characterization techniques aimed at identifying critical substrate-nano-pattern designs maximizing the cubic phase content. Concurrently, the radiative recombination dynamics of these (In)GaN photonic structures will be investigated and their structure-recombination relations correlated. These findings will be quantitatively evaluated in terms of defectivity (± 108 cm-2), phase content (± 0.1%), stress (± 0.01%), alloy content (± 0.01%), crystallographic alignment, bandgap and emission energy (± 1 meV), vibrational energy (± 2 cm-1), recombination dynamics (± 1 ps), and spatial uniformity ( 1.5 nm). The results will also be exploited to improve the radiative recombination dynamics of green light emitting diodes to revolutionize GaN-based photonic device design strategies. The proposed research will be carried out on Complementary Metal-Oxide Semiconductor-compatible silicon substrates to facilitate scalability, industrial adoption, and generate new knowledge on GaN-Silicon heterointegration. The knowledge acquired will help develop new photonic device designs and facilitate a fuller understanding of advanced solid state lighting.