EAGER: A New Approach to Realize (ZnSe)x(GaAs)1-x Alloys for Light Emission and Other Photonics Applications

职务名称：EAGER：一种能够最终实现具有最佳色度的发光器件的单一材料体系摘要非技术描述：尽管在过去55年中在开发用于需要红色、绿色和蓝色发光体的应用的可见光发光二极管（LED）方面取得了巨大的进步，但仍然需要至少两种不同的材料体系来实现仅具有所需的近似色调和色彩特性（色度）的体系。这是一个主要问题，因为必须使用两种不同的材料技术，这给具有红色、绿色和蓝色元素（像素）的显示器（例如公共竞技场的记分牌）的生产增加了很大的成本。此外，当前技术在显示系统中不产生最佳色度。这些系统都不能有效地产生所需的“真”绿色。因此，高成本和非最佳色度的组合已经阻止了用于TV系统的彩色图像的像素化显示器的使用;现代TV系统使用廉价的发射白色的LED作为光源来使液晶像素化TV图像可视化。因此，本研究的目标是进行基础材料科学和构建探索性设备，以实现统一的技术，以降低制造生产成本并改善可见显示应用的色度。这一项目的成功结果具有三方面的广泛影响。首先，它将扩大可视显示器的应用市场，特别是先进的像素化显示系统，包括电视系统。其次，它将增加一个相对未开发的材料系统的基本材料科学和设备工程知识。最后，具有最佳色度的低成本LED将能够“调谐”白色光源，而无需当前需要用磷光体涂覆蓝色发射LED和filtering.Technical Description：本提案的目标是开发晶格匹配的异价化合物半导体材料系统和外延技术，以实现高效和集成的LED，其将覆盖从近红外到蓝色波长的整个光谱，特别是“真绿色”（555 nm波长）。目标材料系统和外延技术分别是在ZnSe或GaAs衬底上的（ZnSe）x（GaAs）1-x外延层和分子束外延（MBE），并且采用新颖的方法来开发均匀的外延层。本研究的具体目标是：1）根据我们的MBE系统的配置，开发用于在GaAs上生长ZnSe的配方，2）确定（ZnSe）x（GaAs）1-x的四元合金的最佳外延生长程序，以及3）制造具有针对“真绿色”LED调整的（ZnSe）x（GaAs）1-x组成的双异质结（DH）器件。利用本研究中获得的知识，可以实现单一的商业材料系统和统一的制造技术，可以生产宽光谱范围的发光器件，激光器和太阳能聚光器芯片。同样重要的是，预计结果将产生积极的转化影响，因为使用（ZnSe）x（GaAs）1-x系统统一光发射器的成功可能会对工业和学术界的光子学社区产生巨大影响，特别是那些生产多色像素阵列的人。这反过来将为社区开辟新的途径，探索新的异质外延原理和利用晶格匹配的异质直接带隙材料系统集成的新应用。

Title: EAGER: A Single Materials System that Could Finally Realize Light Emitting Devices with Optimal ChromaticityAbstractNontechnical Description:In spite of the tremendous progress made in the last 55 years in developing visible Light Emitting Diodes (LEDs) for applications that require red, green, and blue emitters, at least two different materials systems are still required to realize systems having only the approximate hue and colorfulness properties (chromaticity) that is required. This is a major problem because having to use two different materials technologies adds a large cost to the production of displays that have red, green, and blue elements (pixels), such as scoreboards at public arenas. Furthermore, the current technology does not produce optimal chromaticity in the display systems. Neither of these systems can efficiently produce the required "true" green color. Thus, the combination of high cost and non-optimal chromaticity has prevented the use of pixelated displays for color images for TV systems; modern TV systems use inexpensive white emitting LEDs as the light source to visualize the liquid crystal pixelated TV image. Therefore, it is the goal of this research to perform both fundamental materials science and construct exploratory devices that will realize a unified technology to reduce the manufacturing production costs and improve chromaticity for visible display applications. The broader implications of a successful outcome of this project are threefold. First, it will increase the breadth of the application markets for visible displays, especially advanced pixelated display systems, including TV systems. Second, it will add to the fundamental materials science and device engineering knowledge of a relatively unexplored materials system. Finally, low cost LEDs with optimal chromaticity will enable "tuned" white light sources without the current need to coat blue-emitting LEDs with phosphors and filtering.Technical Description:The goal of this proposal is to develop a lattice-matched, heterovalent compound semiconductor materials system and epitaxy technology to realize efficient and integrated LEDs that will cover the entire spectrum from near IR to blue wavelengths, especially "true green" (555 nm wavelength). The targeted materials system and epi-technology is (ZnSe)x(GaAs)1-x epilayers on ZnSe or GaAs substrates and Molecular Beam Epitaxy (MBE), respectively, and employs a novel method to develop homogeneous epilayers. The specific aims of this research are to 1) develop a recipe for the growth of ZnSe on GaAs based on the configuration of our MBE system, 2) identify the optimal epitaxial growth procedure of quaternary alloys of (ZnSe)x(GaAs)1-x, and 3) fabricate Double-Heterojunction (DH) devices with (ZnSe)x(GaAs)1-x composition tuned for "true green" LEDs. With the knowledge gained in this research, a single commercial materials system and a unified fabrication technology that can produce a wide spectral range of light emitting devices, laser, and solar concentrator chips can be realized. Equally important, the results are expected to have a positive translational impact because it is probable that success in unifying light emitters using a (ZnSe)x(GaAs)1-x system would have a huge impact on the photonics community both in industry and academia, especially those who would produce multi-colored pixel arrays. This in turn will open up new avenues for the community to explore both new heterovalent epitaxy principles and new applications that take advantage of integration of lattice-matched heterovalent direct band gap materials systems.