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

Wei, Xiaohuan; Ge, Mengyu; Ke, Shaoqiu; Zu, Shengyan; Kang, Jinyu; Xu, Xiaojia; Li, Zhiming; Chen, Yiliang et al. · Nano Lett · 2026

basic_science · Level V

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Abstract

To address the fundamental limitations of conventional InP/In<sub>0.53</sub>Ga<sub>0.47</sub>As 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 PdSe<sub>2</sub>/InGaAs/InP P-I-N heterojunction photodetector. This structure utilizes the inherent short-wave infrared absorption capability of InGaAs, the broadband absorption of PdSe<sub>2</sub>, and the inherent in-plane optical anisotropy of PdSe<sub>2</sub>, 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.