Near-Infrared, Self-Powered and Polarization-Sensitive Photodetector Based on GeSe-MoTe2 p-n Heterojunction

Near-infrared polarization-sensitive photodetectors hold the advantages of capturing light signals with high performance while shielding stray light, endowing them the potential applications in target tracking, remote sensing, and computer vision. Here, a 2D polarization-sensitive, self-powered, and near-infrared photodetector is constructed by vertically stacking multilayer p-type GeSe on n-type MoTe2. The type-II energy band alignment and anisotropic crystalline structure of GeSe components allow an effective separation and transmission of polarized light excited carriers, enabling the capability of polarization-sensitive and self-powered photodetections. The device exhibits broadband spectral coverage from visible (405 nm) to near-infrared (1310 nm) wavelength range. At zero bias and 808 nm light, the responsivity (R) and detectivity (D*) can reach 52 mA W-1 and 4.1 x 10(11) Jones, respectively. Due to the extremely low dark current of several tens of fA, the photoswitching ratio can reach close to 10(6). More importantly, because of the strong in-plane anisotropic orthogonal structure of GeSe, the polarization sensitivity can reach 5.4 under 635 nm polarized light illumination, outperforming the polarization-sensitive photodetectors based on 2D anisotropic materials and heterostructures. This work provides an effective strategy of using anisotropic/isotropic GeSe/MoTe2 heterojunctions to realize self-powered, near-infrared, and polarization-sensitive photodetectors with integrated angle-resolved optoelectronic devices.