Collaborative Research: NSF-BSF: On-Chip High-Resolution Mid-Infrared Spectroscopy with a Single Tunable van der Waals Heterostructure Photodetector

光谱仪测量光的光谱组成。中红外光谱仪可在2-9 µm光谱范围内工作，可用于许多重要应用，如气体传感、热成像、微生物检测和监视。传统的光谱仪体积庞大、价格昂贵，并且通常由机械运动部件组成。虽然在光谱仪的小型化方面已经取得了重大进展，但目前，大多数紧凑型光谱仪仍然由片上组件阵列组成，以捕获光的不同光谱分量，导致占用面积远远大于工作波长。此外，目前开发紧凑型光谱仪的研究主要集中在可见光和近红外波长范围，而开发集成片上中红外光谱仪的努力非常有限，尽管它们具有技术意义。在该项目中，将开发基于单个片上可调传感器的中红外光谱仪，利用货车德瓦尔斯异质结构和先进的数学算法。拟议的研究涉及新兴材料的光学特性研究、器件制造和数值分析。科学上，这项研究将揭示新兴的货车德瓦尔斯异质结构中的光-物质相互作用特性。结果将导致超紧凑，芯片上的光谱仪在关键的，但较少探索，中红外波长范围。在这个项目中，博士后研究人员，研究生和本科生将获得半导体器件设计和制造方面的知识，从而为半导体行业的下一代劳动力的发展做出贡献。推广活动将提高公众对科学的理解，并鼓励代表性不足的群体从事科学、技术、工程和数学方面的职业。该项目的目标是开发一种基于单个可调谐货车德瓦尔斯异质结构光电探测器的高度紧凑的中红外光谱仪。首先，该团队将从理论和实验上研究中红外波长范围内的货车范德华异质结构中的可调光物质相互作用，为拟议计划奠定基础。第二，可调谐的货车德瓦耳斯异质结构光电探测器将被证明和他们广泛可调的光响应矩阵将在不同的偏置条件下的特点。最后，该团队将开发算法和测量方案，以基于已知的可调光响应特性来演示光谱功能。 该计划旨在开发中红外光谱的新范例。以前的片上光谱仪通常利用多个光电检测元件来检测光的不同光谱分量，并且根据来自这些各种元件的测量来重建光谱。一旦制造完成，这些光电探测元件就不能再进行修改，从而限制了这些光谱仪的分辨率和工作波长范围。所提出的异质结构光谱仪将建立在一种新型的可调谐单元件光电探测器方案的基础上，并进一步利用新兴的货车德瓦尔斯异质结构的有前途的物理特性，以推进芯片上红外光谱的前沿。所提出的光谱仪克服了传统片上光谱仪的分辨率限制，并使光谱功能的足迹内的操作波长相当。该项目是高度跨学科的，利用材料科学、凝聚态物理和电气工程的最新发展，提供备受期待的、变革性的货车德瓦尔斯材料应用。该奖项反映了NSF的法定使命，并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，被认为值得支持。

Spectrometers measure the spectral composition of light. Mid-infrared spectrometers, operational in 2-9 µm spectral range, can be used in many important applications such as gas sensing, thermal imaging, microbial detection, and surveillance. Traditional spectrometers are bulky, expensive, and usually consist of mechanically moving parts. Although significant progress has been made in the miniaturization of spectrometers, currently, most compact spectrometers still consist of an array of on-chip components to capture the different spectral components of the light, leading to a footprint much larger than the operational wavelength. Moreover, current research on developing compact spectrometers focuses on visible and near-infrared wavelength range, and the effort on developing integrated on-chip mid-infrared spectrometers is very limited despite their technical significance. In this project, mid-infrared spectrometers based on a single, on-chip, tunable sensor will be developed, leveraging van der Waals heterostructures and advanced mathematical algorithms. The proposed research involves investigations of the optical properties of emerging materials, device fabrication, and numerical analysis. Scientifically, this research will reveal the light-matter interaction properties in emerging van der Waals heterostructures. The results will lead to ultracompact, on-chip spectrometers in the critical, but less-explored, mid-infrared wavelength range. In this project, postdoctoral researchers, and graduate and undergraduate students will acquire knowledge in semiconductor device design and fabrication, thus contributing to the development of next-generation workforce for semiconductor industry. The outreach activities will improve the scientific understanding of the general public and encourage underrepresented groups to pursue careers in science, technology, engineering, and math. The goal of this project is to develop a highly compact, mid-infrared spectrometer based on a single, tunable van der Waals heterostructure photodetector. First, the team will investigate the tunable light-matter interactions in van der Waals heterostructures in the mid-infrared wavelength range both theoretically and experimentally, laying the foundation for the proposed program. Second, tunable van der Waals heterostructure photodetectors will be demonstrated and their widely tunable photoresponse matrices will be characterized under different biasing conditions. Finally, the team will develop algorithms and measurement schemes to demonstrate spectroscopy functions based on the known tunable photoresponse characteristics. The proposed program aims to develop new paradigms for mid-infrared spectroscopy. Previous on-chip spectrometers usually utilize multiple photodetection elements to detect different spectral components of the light, and the spectrum is reconstructed from measurements from these various elements. Once fabricated, these photodetection elements can no longer be modified, thus limiting the resolution and the operational wavelength range of these spectrometers. The proposed heterostructure spectrometer will build upon a novel tunable single-element photodetector scheme, and further leverage the promising physical properties of emerging van der Waals heterostructures to advance the frontiers of on-chip infrared spectroscopy. The proposed spectrometer overcomes the resolution limitations of traditional on-chip spectrometers and enables spectroscopic functionality within a footprint comparable to the wavelength of the operation. The project is highly interdisciplinary and leverages latest developments in material sciences, condensed matter physics, and electrical engineering to deliver much-anticipated, transformative applications with van der Waals materials.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.