The discovery of ferromagnetism in van der Waals (vdW) materials has enriched the understanding of two-dimensional (2D) magnetic orders and opened new avenues for fundamental physics research and next generation spintronics. However, achieving ferromagnetic order at room temperature, along with strong perpendicular magnetic anisotropy, remains a significant challenge. In this work, we report wafer-scale growth of vdW ferromagnet Fe₃GaTe₂ using molecular beam epitaxy. The epitaxial Fe₃GaTe₂ films exhibit robust ferromagnetism, exemplified by high Curie temperature (T_C = 420 K) and large perpendicular magnetic anisotropy (PMA) constant K_U = 6.7 × 10⁵J/m³ at 300 K for nine-unit-cell film. Notably, the ferromagnetic order is preserved even in the one-unit-cell film with T_C reaching 345 K, benefiting from the strong PMA (K_U = 1.8×10⁵J/m³ at 300 K). In comparison to exfoliated Fe₃GaTe₂ flakes, our epitaxial films with the same thickness show the significant enhancement of T_C, which could be ascribed to the tensile strain effect from the substrate. The successful realization of wafer-scale ferromagnetic Fe₃GaTe₂ films with T_C far above room temperature represents a substantial advancement (in some aspects or some fields, e.g. material science), paving the way for the development of 2D magnet-based spintronic devices.

Flexible photodetectors with ultra‐broadband sensitivities, fast response, and high responsivity are crucial for wearable applications. Recently, van der Waals (vdW) Weyl semimetals have gained much attention due to their unique electronic band structure, making them an ideal material platform for developing broadband photodetectors from ultraviolet (UV) to the terahertz (THz) regime. However, large‐area synthesis of vdW semimetals on a flexible substrate is still a challenge, limiting their application in flexible devices. In this study, centimeter‐scale type‐II vdW Weyl semimetal, T_d‐MoTe₂ films, are grown on a flexible mica substrate by molecular beam epitaxy. A self‐powered and flexible photodetector without an antenna demonstrated an outstanding ability to detect electromagnetic radiation from UV to sub‐millimeter (SMM) wave at room temperature, with a fast response time of ≈20 µs, a responsivity of 0.53 mA W⁻¹ (at 2.52 THz), and a noise‐equivalent power (NEP) of 2.65 nW Hz^−0.5 (at 2.52 THz). The flexible photodetectors are also used to image shielded items with high resolution at 2.52 THz. These results can pave the way for developing flexible and wearable optoelectronic devices using direct‐grown large‐area vdW semimetals.