The van der Waals (vdW) materials offer an opportunity to build all-two-dimensional (all-2D) spintronic devices with high-quality interfaces regardless of the lattice mismatch. Here, we report on an all-2D vertical spin valve that combines a typical layered semiconductor MoS 2 with vdW ferromagnetic metal Fe 3 GeTe 2 (FGT) flakes. The linear current−voltage curves illustrate that Ohmic contacts are formed in FGT/MoS 2 interfaces, while the temperature dependence of the junction resistance further demonstrates that the MoS 2 interlayer acts as a conducting layer instead of a tunneling layer. In addition, the magnitude of the magnetoresistance (MR) of 3.1% at 10 K is observed, which is around 8 times larger than that of the reported spin valves based on MoS 2 sandwiched by conventional ferromagnetic electrodes. The MR decreasing monotonically with increasing temperature follows the Bloch's law. As the bias current decreases exponentially, the MR increases linearly up to a maximum value of 4.1%. Our results reveal the potential opportunities of vdW heterostructures for developing novel spintronic devices.

Graphene and graphene‐like 2D layered materials such as black phosphorus, transition‐metal dichalcogenides, oxides, chalcogenides, and so forth have attracted tremendous attention due to their unique crystal structures, mechanical, and physical properties, as well as their variable bandgaps that range from 0 to 6 eV, which have offered their utilization in versatile devices. Using these materials as the active channel, many novel electrical and optoelectronic devices have been reported. Among the various important devices applications, photodetectors based on 2D materials have been extensively investigated with varied performance due to the different species and detection mechanisms. Here, the methods to improve the performance of 2D‐material‐based photodetectors are reviewed. There are five kinds of strategies regarding methods, including surface plasmon enhancement, charge‐transfer assistance, optical‐waveguide integration, graphene sandwiched structures, and heterostructures directly grown by CVD, which are developed and widely reported in recent years. For each method, the device design, performance, and mechanism are introduced and discussed systematically. Finally, a summary is provided to afford the principle to further enhance the performance of photodetectors based on 2D materials, with a perspective for their practical applications in the future.