碳纳米管-硅波导在片混合集成光接收器的研究

Owing to its unique electrical and optical properties, especially their superb mobility, direct bandgap and wide optical response range which can cover from UV to mid-infrared, photo response speed which can reach up to ps, and carbon nanotubes thin film can integrate with other devices as a quasi-two-dimensional material, carbon nanotube has been considered as a promising material to build OEIC systems. In this project, combining the advantages of carbon nanotubes and silicon, we aim to explore fabricating hybrid on-chip photoreceiver based on carbon nanotube thin film and silicon waveguide, measuring and investigating their performance, and provide a scheme to optimizing the performance. In detailed, the research works should focus on four aspects as follows, 1. Determining the optimal thickness of the carbon nanotube thin film, by investigating the relationships between the thickness of carbon nanotube thin films and light absorption efficiency and photoelectric conversion efficiency. 2. Fabricating the CNTs waveguide detector on silicon waveguide sample. 3. Building the on-chip integration of CNTs waveguide hybrid detectors and carbon nanotube thin film based integrated circuits and TIA. 4. Establishing models by using parameters of devices such as photoresponse, bandwidth and dark current et al., and then exploring the theoretical limit of the CNTs waveguide detector and photoreceiver, and determining the optimization scheme. At the end, evaluating the prospect of CNTs-Si hybrid on-chip integration in the field of optical interconnection in future.

在片混合光电集成是未来光电集成的发展方向。碳纳米管有着独特的电学和光学性能，特别是其超高的载流子迁移率，直接带隙且覆盖紫外到中红外波段的光响应范围，皮秒量级的光响应速度，以及碳纳米管薄膜兼具二维材料易与硅基波导集成等特性，在构建混合在片光电集成系统方面极具潜力。本项目中，我们预结合碳纳米管和硅基的优势构建用于光通信的混合接收器，探索碳纳米管薄膜-硅基混合在片光电集成的可能性。具体研究目标：1.研究碳纳米管薄膜厚度与光吸收率和光电转化效率之间的关系，确定碳纳米管薄膜厚度最佳值。2.制备出碳纳米管薄膜硅（CNTs-Si）波导混合探测器。3.探索基于CNTs-Si波导混合探测器与碳纳米管放大器和电路的在片集成光接收器。4.建立模型，探索CNTs-Si波导混合探测器及光接收器工作的理论极限，确定优化方案。在此基础上进一步评估CNTs-Si混合在片集成在未来光互联领域的前景。

光电集成是光通信和光计算的重要研究方向，工艺简单且兼容的在片光电集可有效促进光电集成的发展。准一维材料碳纳米管具有超高载流子迁移率，直接带隙且光响应范围覆盖紫外到中红外波段，皮秒量级的光响应速度，可大规模制备和易与硅基波导集成等特性，在构建在片光电集成系统方面极具潜力。在项目研究中，我们从研究波导结构中碳纳米管薄膜的光吸收效率出发，研究了不同结构碳纳米管硅波导混合探测器的性能，构建了碳纳米管硅波导混合探测器和碳纳米管无掺杂CMOS放大系统的在片集成系统，最后建立模型分析了碳纳米管硅波导混合探测器及光接收器截止频率的理论极限。经过四年的研究，目前项目取得以下成果：1. 首次通过实验测试了波导中碳纳米管薄膜的光吸收效率为0.06 dB/μm，与相同结构其他二维材料的光吸收系数相比，该实验结果说明了碳纳米管较适用于通信波段的在片集成探测器；2. 制备了p-i-n结构，M-S-M结构，异质结构的碳纳米管硅波导混合探测器，通过比较响应度，带宽和功耗等参数，证明了三种结构中p-i-n结构为碳纳米管硅波导混合探测器的最佳结构。经过优化后，实现了零偏下带宽为48 GHz的光电探测器；3. 实验实现了碳纳米管硅波导混合探测器，碳纳米管CMOS放大系统和或非门的在片集成，并进一步用两个波导探测器，一个或非门和多模干涉分束器模拟了波分复用体系的流程，验证了碳纳米管硅波导混合探测器和电路在片集成的可能性和潜力；4. 构建模型分析了优化后碳纳米管硅波导混合探测器的带宽及其受限因素，分析结果与实验结果吻合。构建模型分析了碳纳米管CMOS放大系统的截止频率及受限因素，为后续碳纳米管硅波导混合光接收机在T比特光通信系统中的应用提供了研究思路。