High-performance polarization-sensitive photodetector based on a few-layered PdSe₂ nanosheet

The extraordinary optical and electronic properties of anisotropic two-dimensional materials, such as black phosphorus, ReS₂, and GeSe, enable them a promising component of polarization-sensitive photodetectors. However, these applications are significantly limited by the challenges of air-stability, response time, and linearly dichroic ratio. Interestingly, palladium diselenide (PdSe₂) with high air stability is an emerging material that has robust in-plane anisotropy induced by its asymmetric pentagonal lattice structure. We have successfully prepared a few-layer PdSe₂ using micromechanical exfoliation, and here we demonstrate the strong linear dichroism behavior of PdSe₂ by polarization-resolved absorption spectra measurements. Such unique linear dichroism, endows the PdSe₂ photodetector powerful ability to detect polarized light. The photodetector based on 5L PdSe₂, as tested with polarization-dependent photocurrent mapping, exhibited competitive capability to detect polarized light, achieving a significant photocurrent on/off ratio (> 10²), the quite fast response time (< 11 ms) and robust linearly dichroic ratios (I_max/I_min ≈ 1.9 at 532 nm). These results are essential advance in the development of polarization-sensitive photodetector, a crucial step towards opening up a new avenue for the application of 2D optoelectronic devices.