Waveguide Integrated Self-Powered MoS ₂ Photodetectors in the Shortwave Infrared Wavelengths

Broadband photodetectors (PDs) are essential for various applications, including optical communication, sensing, and imaging. Modern semiconductor PD technologies often face challenges related to spectral coverage, power consumption, complex manufacturing, and limited integration with silicon electronics. As photonics technologies continue to advance alongside growing performance demands, exploring new avenues for innovative, cost-effective broadband PDs with reduced power consumption and manufacturing complexity is becoming increasingly important. In this work, we present a zero-bias, waveguide-integrated PD based on single-layer MoS₂, which operates at telecom wavelengths with no dark current. By utilizing the photothermoelectric effect combined with internal photoemission process, our devices demonstrate a record responsivity of ∼180 V/W at 1550 nm, the highest reported in the literature for unbiased 2D PDs operating in the short-wave infrared. The recorded frequency response is in the millisecond range, limited by the electrical RC time constant. The PD noise equivalent power is ∼500 nW at 1 Hz, dominated by 1/<i>f</i> noise, and is reduced to ∼0.3 nW at the Johnson limit. Consequently, the specific detectivity (<i>D</i>*) is estimated to be ∼10⁵ Jones at the 1/<i>f</i> limit, reaching ∼2 × 10¹⁰ Jones at Johnson noise-limited operation. Our findings contribute to developing high-efficiency broadband MoS₂ PDs and emphasize the potential of 2D semiconductors in advancing self-powered PDs technology.