On-Chip Polarimetric Photodetector with High Polarization Extinction Ratio and Extended SWIR Response Using PdSe ₂ /InGaAs/InP Vertical P-I-N Heterostructure

To address the fundamental limitations of conventional InP/In_0.53Ga_0.47As P-I-N photodetectors, including their narrow spectral response range, low responsivity, and lack of intrinsic polarization sensitivity, this study demonstrates a Si-based vertical PdSe₂/InGaAs/InP P-I-N heterojunction photodetector. This structure utilizes the inherent short-wave infrared absorption capability of InGaAs, the broadband absorption of PdSe₂, and the inherent in-plane optical anisotropy of PdSe₂, the device achieves record responsivities of 2.59 A/W at 1310 nm (3-fold to 5-fold beyond theoretical limits), 0.628 A/W (1550 nm), 8.99 mA/W (1850 nm), and 2.67 mA/W (2200 nm), extending detection beyond the cutoff wavelength of InGaAs. Exceptional polarization sensitivity yields polarization extinction ratios of 85.5 (1310 nm), 408.6 (1550 nm, 10-fold higher than state-of-the-art), 106.2 (1850 nm), and 55.5 (2200 nm). This synergy of anisotropy, junction carrier separation, and P-I-N architecture enables on-chip polarization-sensitive IR systems without external optics.