High-Performance Self-Driven Polarization-Sensitive Imaging Photodetectors based on Fully Depleted T-MoSe2/GeSe/B-MoSe2 Van der Waals Dual-Heterojunction

Abstract

New 2D materials with low-symmetry structures aroused great interest in developing monolithic polarization-sensitive photodetectors with small volumes, which can provide a new degree of freedom for more information in night, fog, and smoke environments. However, at least half of them presented a small anisotropy with an anisotropic factor (≈2) of photocurrent up to now. Herein, after systematic investigation of the optical anisotropies of GeSe nanosheets, a novel self-driven polarization-sensitive imaging photodetector with excellent performance based on a Top-MoSe2/GeSe/Bottom-MoSe2 (T-MoSe2/GeSe/B-MoSe2) van der Waals dual-heterojunction is proposed. Benefitting from the effective separation and shortening transmission distance of photocarriers by fully depleted Van der Waals dual-heterojunction on both sides of in-plane anisotropy of GeSe, the anisotropic photocurrent ratio (Imax/Imin) of T-MoSe2/GeSe/B-MoSe2 photodetector can reach as high as 12.5 (635 nm, 0 V). This value is 3.5-fold higher than that of MoSe2/GeSe photodetector, and 7-fold higher than that of the pristine GeSe photodetector in this work. The responsivity of the T-MoSe2/GeSe/B-MoSe2 photodetector (206 mA W−1, 0 V) is 5 times higher than that of the MoSe2/GeSe photodetector. In addition, the T-MoSe2/GeSe/B-MoSe2 photodetector exhibited a high light on/off ratio of 4 × 104 at 0 V. This work provides novel insights for developing high-performance polarization-sensitive imaging photodetectors.