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

非技术描述：尽管在过去55年中在开发用于需要红、绿和蓝发射器的应用的可见光发射二极管(LED)方面取得了巨大的进步，但仍需要至少两种不同的材料系统来实现仅具有所需的近似色调和色彩特性(色度)的系统。这是一个大问题，因为必须使用两种不同的材料技术增加了具有红、绿和蓝元素(像素)的显示器的生产成本，例如公共竞技场的记分牌。此外，当前技术不能在显示系统中产生最佳色度。这两种系统都不能有效地产生所需的“真实”绿色。因此，高成本和非最佳色度的组合阻碍了用于电视系统的彩色图像的像素化显示器的使用；现代电视系统使用廉价的白色发光LED作为光源来可视化液晶像素化的电视图像。因此，这项研究的目标是既进行基础材料科学研究，又构建探索性器件，以实现统一的技术，以降低制造成本并提高可见光显示应用的色度。该项目取得成功的更广泛的影响有三个方面。首先，它将增加可视显示器的应用市场的广度，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被探索的材料系统的基础材料科学和设备工程知识。最后，具有最佳色度的低成本LED将使白光光源能够调谐，而不需要在蓝光LED上涂上荧光粉和滤光片。技术描述：这项提议的目标是开发一种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，将覆盖从近红外到蓝色波长，特别是“真绿”(555 nm波长)的整个光谱。靶材系统和外延技术分别是在ZnSe或GaAs衬底上生长(ZnSe)x(GaAs)1-x外延层和分子束外延(MBE)，并采用了一种新的方法来制备均匀的外延层。本研究的具体目标是：1)根据我们的分子束外延系统的结构，开发一种在GaAs基上生长ZnSe的配方；2)确定(ZnSe)x(GaAs)1-x四元合金的最佳外延生长工艺；3)制作具有适合“真绿”发光二极管的(ZnSe)x(GaAs)1-x组分的双异质结器件。通过这项研究获得的知识，可以实现单一的商业材料体系和统一的制造技术，可以生产多种光谱范围的发光器件、激光和太阳能聚光器芯片。同样重要的是，这些结果预计将产生积极的平移影响，因为成功地统一使用(ZnSe)x(GaAs)1-x系统的光发射器很可能会对工业界和学术界的光电子界产生巨大影响，特别是那些将生产多色像素阵列的人。这将为社区探索新的异价外延原理和利用晶格匹配的异价直接带隙材料系统的新应用开辟新的途径。

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.