Highly in-plane anisotropic 2D ReSe₂ for polarization-sensitive photodetectors

Here we report a new member of in-plane anisotropic 2D materials Rhenium Diselenide (ReSe₂) which holds a stable distorted 1 T’ phase with its relatively narrow bandgap to explore the in-plane anisotropic structural, electrical, and optical properties. The proposed polarization-sensitive photodetectors based on few-layer ReSe₂ provides highly anisotropic photodetection behavior with linearly dichroic ratio up to ≈2.62 under 808 nm illumination. We measured carrier transport in space and time by mapping carrier density in a ReSe₂ plate using transient absorption microscopy. These results directly determined the carrier diffusion coefficients of about 4100 cm² s^-1 and 2900 cm² s^-1 along the armchair and zigzag directions, respectively, providing fundamental parameters to better understand the anisotropy of ReSe₂ and promote future 2D optoelectronic applications in polarization-sensitive detection.