High-Speed Compact Plasmonic-PdSe<sub>2</sub> Waveguide-Integrated Photodetector
Jialing Jian, Jianghong Wu, Chuyu Zhong, Hui Ma, Boshu Sun, Yuting Ye, Ye Luo, Maoliang Wei, Kunhao Lei, Ruizhe Liu, Zequn Chen, Guangyi Li, Hao Dai, Renjie Tang, Chunlei Sun, Junying Li, Wei Li, Ming Li, Hongtao Lin, Lan Li
Abstract
Waveguide-integrated photodetectors are essential components in integrated photonic circuits since they facilitate light conversion into electrical signals. Nonetheless, optical absorption and carrier collection can significantly affect the device performance. As a solution to this issue, plasmonic slot waveguides confine optical energy within a subwavelength scale in a photoconductive detector, enhancing optical absorption and providing extremely short channels to collect carriers. Two-dimensional van der Waals layered palladium selenide (PdSe 2 ) exhibits the merits of a narrow bandgap and high carrier mobility, thus positioning it as a favorable candidate material for photodetectors operating at the telecommunication band. In this study, we propose and experimentally verify a high-speed PdSe 2 -plasmonic waveguide-integrated photodetector with a dark current of 4.5 μA and an intrinsic responsivity of 560.1 mA·W −1 at 3 V. Additionally, it has an internal quantum efficiency of 32.3%, and the measured 3 dB bandwidth is 17.5 GHz. This integrated photodetector fulfills the requirements of various critical applications in optical communication, microwave photonics, sensing, and imaging.