Si‐Based GeSn Lateral p–i–n Waveguide Photodetectors Covering Entire Short‐Wave Infrared Band

GeSn has emerged as a promising alternative in Si photonics due to its narrow and tunable bandgap. In this study, GeSn waveguide photodetectors (WGPDs) based on a lateral p–i–n homojunction architecture are demonstrated. Incorporating 10.82% Sn effectively reduces the bandgap, extending the photodetection range to 2745 nm and covering the entire short‐wave infrared (SWIR) region. A lateral p–i–n homojunction diode with good optical confinement and long photon‐absorbing length is developed to significantly enhance the optical responsivity. The close proximity of the direct (Γ c ) and indirect ( L c ) conduction bands allows excitation of electrons from Γ c to L c , increasing electron lifetime. As a result, the carrier collection efficiency improves with higher bias. This momentum‐space separation mechanism enables device operation at a low electric field of ≈2.5 kV cm −1 . These findings suggest that the fabricated GeSn WGPDs are strong candidates for full‐range SWIR detection applications.