Vertical Van Der Waals Epitaxy of p‐MoxRe1‐Xs2 on GaN for Ultrahigh Detectivity Uv–vis–NIR Photodetector

van der Waals (vdW) heterogeneous integration and doping engineering have emerged as crucial factors in advancing the development of functional device systems. This work presents a fully vertical 2D/3D vdW stacking p‐MoxRe1‐xS2/GaN (x = 0.10 ± 0.02) heterojunction photodetector, integrating multiple strategies for enhanced performance, such as mixed‐dimensional stacking, p‐type doping, vertical device design, and type‐II band alignment. By integrating horizontal, vertical, and quasi‐vertical devices on a Free‐standing (FS)‐GaN substrate, the vertical p‐MoxRe1‐xS2/GaN device demonstrates superior performance, including high Ilight/Idark ratio (1.48 × 106), large Responsivity (888.69 AW−1), high specific detectivity (D*) (6.13 × 1014 Jones), and fast response speed (rise/decay time of 181 ms/259 ms). Moreover, the spectral response encompasses the ultraviolet (UV), visible, and near‐infrared (NIR) regions through energy band integration and bandgap modulation. This design surpasses previous devices, highlighting the potential of highly sensitive and micro‐integrated optoelectronic devices enabled by vertical vdW heterogeneous integration. Large‐area p‐MoxRe1‐xS2 films are grown on Free‐standing GaN substrates using one‐step CVD. A fully vertical vdW heterostructure photodetector exhibits improved performance with a high photo Ion/Ioff ratio (1.48 × 106), specific detectivity (D*) (7.13 × 1014 Jones), and fast response time (181 ms/259 ms). Enhancements are attributed to the built‐in electric field and type‐II band alignment at the p‐MoxRe1‐xS2/GaN interface. The vertical structure avoids etching damage and utilizes internal carriers in bulk GaN, enhancing electronic and optoelectronic device performance.