EAGER: Lattice-matched direct-bandgap III-V photodetector materials to silicon

第一部分：主要由硅晶体制成的电子集成电路改变了人类计算和交换信息的方式。 这一进步是由于电子集成电路制造技术的发展而实现的。 这种制造基础设施也使其他领域取得了巨大的进步，例如太阳能电池和数码相机，其中硅用于将入射光转化为电能/电流。 然而，硅敏感的光的颜色范围以及它可以检测光的速度从根本上受到限制。 在这里，我们寻求研究一种新的材料家族，该材料家族具有在硅不敏感的红外线中感测光的颜色的潜力，并且大大提高了检测速度，其应用包括自动驾驶汽车，通信系统和生物医学仪器。 关键优势在于，这些新材料与硅共享兼容的晶体结构，可能使它们能够直接在硅上生长为晶体，并利用复杂的硅制造基础设施。 该项目的目标是回答与增强硅上光探测潜力相关的关键问题。 该项目将为两名博士提供前沿研究机会。第二部分：目前的方法对单片集成的直接带隙材料的硅遭受各种挑战，并没有明确的路径晶格匹配的材料需要解决重要的新兴应用在近红外和中红外。特别是对于光电探测器，晶格匹配对于避免困扰变形方法的过多暗电流至关重要。 虽然硅本身可以是一种非常有效的光电探测器，但它的光谱覆盖范围限于小于~1.1微米，并且高量子效率所需的厚吸收区域往往将可实现的带宽限制在小于~2 GHz。该项目将重点关注BGaAs和BGaInAs光电探测器的潜力，这些光电探测器可以在硅上跨越约1-5微米的截止波长，并由于其直接带隙而提供显着的带宽优势。 它的基础是（1）PI？？最近成功地将创纪录的高达22%的硼含量引入GaAs中，几乎足以与硅晶格匹配，（2）初步的金属-半导体-金属BGaAs光电探测器，（3）在GaP上成功地初步生长直接带隙BGaAs，以及（4）GaP-on-Si衬底的商业可用性。 该项目将回答关键问题，这些问题决定了这些新兴材料用于光电探测器的潜在可行性，这些材料与p型和n型掺杂，缺陷缓解和基本光学特性有关。 此外，晶格匹配的BGaAs上的GaP-on-Si模板将被证明是第一次，沿着与铟合金，以产生可调带隙BGaInAs合金晶格匹配的硅。 虽然这里的重点将是解决直接带隙晶格匹配的光电探测器的要求，重要的是要注意，这些研究成果中的大部分可以适用于emitter以及。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Part 1:The electronic integrated circuit, built primarily of crystals of silicon, has transformed the way humans compute and exchange information. This progress been enabled by the development of ever more powerful manufacturing techniques for electronic integrated circuits. This manufacturing infrastructure has also enabled tremendous advances in other areas, such as solar cells and digital cameras, where silicon is used to turn incident light into electrical energy/current. However, the range of colors of light to which silicon is sensitive, as well as the speed with which it can detect light, are fundamentally limited. Here, we seek to study a new family of materials that offers the potential for sensing colors of light in the infrared to which silicon is not sensitive, as well as greatly increased speed of detection, with applications including autonomous vehicles, communication systems, and biomedical instrumentation. The key advantage is that these new materials share a compatible crystal structure with silicon, potentially allowing them to be grown as crystals directly on silicon and take advantage of the sophisticated silicon manufacturing infrastructure. The goal of this project is to answer key questions related to the potential to enhance light detection on silicon. This project will provide cutting-edge research opportunities for two Ph.D. students, increase research opportunities for undergraduates from historically underrepresented groups, and engage pre-K to 12 students with the exciting world of nanoscience.Part 2:Current approaches towards monolithic integration of direct bandgap materials on silicon suffer from a variety of challenges and there is no clear path to the lattice-matched materials needed to address important emerging applications in the near- and mid-infrared. For photodetectors specifically, lattice-matching is critical to avoid the excessive dark currents that plague metamorphic approaches. While silicon itself can be an extremely efficient photodetector, it is limited in spectral coverage to less than ~1.1 micron and the thick absorbing regions required for high quantum efficiency tend to limit achievable bandwidths to less than ~2 GHz. This project will focus on the potential for BGaAs and BGaInAs photodetectors, which could span ~1-5 micron cutoff wavelengths on silicon and offer dramatic bandwidth advantages due to their direct bandgap. It is underpinned by (1) the PI??s recent success incorporating record high boron contents up to ~22% into GaAs, nearly sufficient to lattice-match with silicon, (2) preliminary metal-semiconductor-metal BGaAs photodetectors, (3) successful initial growths of direct bandgap BGaAs on GaP, and (4) the commercial availability of GaP-on-Si substrates. This project will answer key questions that govern the potential viability of these emerging materials for photodetectors related to p- and n-doping, defect mitigation, and fundamental optical properties. Additionally, lattice-matching of BGaAs onto GaP-on-Si templates will be demonstrated for the first time, along with alloying with indium to produce tunable-bandgap BGaInAs alloys lattice-matched to silicon. While the focus here will be on addressing the requirements for direct bandgap lattice-matched photodetectors, it is important to note that much of these research findings could be applicable to emitters as well.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.