[TuD4] Photo Detection Technologies

5:45 PM - 6:00 PM JST(8:45 AM - 9:00 AM UTC)

[TuD4-05] High-Responsivity InGaAs MSM Photodetector with Narrow-Gap-Parallel-electrode Configuration Integrated on Si Waveguide

〇Kentaro Komatsu¹, Tomohiro Akazawa¹, Stéphane Monfray², Frederic Boeuf², Kasidit Toprasertpong¹, Mitsuru Takenaka¹ (1. The Univ. of Tokyo (Japan), 2. STMicroelectronics (France))

In metal-semiconductor-metal (MSM) photodetectors, reducing the electrode gap is generally required for high-speed operation, however, most previously reported waveguide-integrated devices employ electrode gaps larger than 700 nm, and narrow-gap parallel-electrode structures remain largely unexplored. In this study, we demonstrate MSM photodetector integration by bonding an InGaAs membrane onto a Si waveguide and forming parallel electrodes with narrow gaps along the optical propagation direction. This configuration enhances optical confinement in the InGaAs layer, enabling reduction of carrier transit time without sacrificing responsivity. A high responsivity of 0.95 A/W was achieved in a device with a 300-nm-wide electrode gap and a 5-μm-long active region, demonstrating that high-responsivity can be maintained even with a narrow electrode gap in MSM photodetectors.