Electrical Injection Nanolasers Based on 2D Monolayer Gain Material

纳米激光器具有广泛的应用前景，特别是在未来计算机集成纳米光子电路的光互连中。尽管取得了很大的进展，但目前还没有这样的光源满足未来片上互连的严格要求。目前的半导体激光器每传输一个信息消耗约0.1-1皮（万亿分之一）焦耳的能量；然而，所需的激光器每比特消耗的能量必须小于0.01皮焦耳，这反过来又限制了这种激光器的尺寸为100纳米，以取代电子互连。该项目将重点放在基础研究上，以开发具有高能效的纳米级光源。如果成功，这项研究将对社会、经济和教育产生深远的影响：1)解决能源效率问题，因为与互联网相关的能源消耗正在以远远超过当前不断增长的能源生产能力的速度增长；2)通过纳米光子器件设计、纳米制造和未来计算机技术的开发，培养本科生和研究生，特别是来自代表性不足群体的学生从事绿色光子技术的研究和开发。纳米级激光器需要两个关键成分：一个限制光子的小腔和有效的光学增益材料。过渡金属二硫族化合物（TMDCs）的二维层状材料是近年来出现的最有效和最小体积增益介质之一。最近的研究表明，激光仅使用单层TMDCs。这些研究表明，二维材料可能是最有效的增益材料。但是到目前为止，所有的实验都需要光泵浦，而它们在电注入下的操作对于芯片上的应用是必要的。提出的努力旨在开发第一个基于二维TMDCs的电注入纳米激光器，以解决能源效率的基本挑战。该方法将最有效的二维TMDCs光学增益材料与高质量的硅腔相结合，以制造最节能的纳米激光器。在激子跃迁上运行的二维材料为纳米激光器提供了几个好处：最有效的光学增益材料，实现激光的最小增益体积，以及易于集成到硅平台中。硅纳米束腔提供了最高的质量因子和最低的激光阈值，同时提供了与电子兼容和制造成熟的优势。这种硅平台上的电注入纳米激光器非常适合于光互连和其他基于硅的应用。本课题的目标是通过优化设计研究载流子注入二维单层二碲化钼，通过理论设计和模拟与实验制作和表征相结合，实现在硅平台上使用二维增益材料的第一个电注入纳米激光器。实现这一目标将为开发用于未来节能计算机的传感和芯片级互连的各种未来设备奠定基础。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nanoscale lasers are important for a wide range of applications, especially in optical interconnects for integrated nanophotonic circuits in future computers. Despite great progress made, no such light source currently meets the stringent requirements of future on-chip interconnects. Current semiconductor lasers consume ~ 0.1-1 pico (one trillionth) joule of energy per bit of information transmitted; however, the required lasers must consume less than 0.01 pico-joule of energy per bit, which in turn limits the dimensions of such lasers to 100s of nanometers to displace electronic interconnects. The proposed project focuses on fundamental research to develop such nanoscale light sources with high energy efficiency. If successful, the research would have far reaching societal, economical, and educational impacts by 1) addressing energy efficiency issue, because the amount of internet-related energy consumption is increasing at a rate that far exceeds the current increasing capacity of energy generation; 2) training undergraduate and graduate students, especially those from the underrepresented groups, in research and development of green-photonic technology through nanophotonic device design, nano-fabrication, and the development of future computer technologies.Nanoscale lasers require two key ingredients: a small cavity to confine photons and efficient optical gain materials. One of the most efficient and smallest-volume gain media emerged recently is the two-dimensional (2D) layered materials of transition metal di-chalcogenides (TMDCs). Recent research has demonstrated lasing using only a single layer of TMDCs. These studies have demonstrated 2D materials as potentially the most efficient gain materials. But all experiments to date have required optical pumping, while their operation under electrical injection is necessary for on-chip applications.The proposed efforts aim at developing the first electrical-injection nanolasers based on 2D TMDCs to address the fundamental challenges of energy efficiency. The proposed approach combines the most efficient optical gain material of 2D TMDCs with high-quality silicon cavities to fabricate the most energy-efficient nanolasers. The 2D materials operating on excitonic transitions provide several benefits to nanolasers: the most efficient optical gain material, the smallest gain volume to achieve lasing, and ease of integration into a silicon platform. The Si-nanobeam cavity provides the highest quality factor with the lowest possible laser threshold, while offering advantages of compatibility with electronics and maturity in fabrication. Such an electrical injection nanolaser on a Si-platform is ideally suited for optical interconnects and other Si-based applications.The objective of the proposal is to study the carrier injection into 2D monolayer molybdenum ditelluride with optimized design to achieve the first electrical injection nanolaser using a 2D gain material on a Si-platform by combining theoretical design and simulation with experimental fabrication and characterization. Achieving this objective would lay the ground work for development of a variety of future devices for use in sensing and chip-level interconnects for future energy-efficient computers.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.