Direct observation of enhanced performance in suspended ReS₂ photodetectors

Rhenium disulfide (ReS₂) has emerged as a promising material for future optoelectric applications due to its extraordinary electrical, mechanical, and optoelectrical properties. However, the ReS₂-based photodetectors are severely restricted by their slow response speed (>10 s). Here, we demonstrate a high-performance polarization-sensitive photodetector based on suspended ReS₂. Such a transistor shows an n-type behavior with the mobility of about 14.1 cm²V^-1s^-1, an on/off ratio of 10⁵, and a responsivity of 0.22 A/W. Benefitting from well-developed contact between Au and the ReS₂ channel and reduced interface scattering from the Si substrate, the response time of the device can be as short as 83.5 and 325.3µs, respectively, which are three orders of magnitude faster than that reported earlier. Furthermore, the suspended ReS₂ photodetector also has the capability to detect polarized light (I_max/I_min ≈ 1.4 at 532 nm) due to the robust in-plane anisotropy of the material. These findings offer an efficient approach for improving the performance of ReS₂-based photodetectors.