process technology and the potential for large-scale integration of photodetector networks with readout circuits. [3,4] The device performance of Si-based SBD photodetectors is fundamentally determined by the Schottky barrier height (Ф B ) between the metallic electrode and Si. A high Ф B is much desired for self-powered SBD photodetectors, because the large built-in electric field arising from the high Ф B could effectively enhance the separation and transportation of photo-generated carriers. According to the Schottky-Mott model, [5] the Ф B predominantly dependent on the metal function as well as the interface quality of the metal/semiconductor contact. Although a Ф B value up to 0.9 eV was achieved for these Si-based SBDs, they encounter similar challenges in terms of severe interface metal diffusion and low light transparency.Recently, a new class of 2D transition metal carbides and nitrides, called MXenes, [6] has spurred great research interest as promising building blocks for optoelectronic device applications. [7][8][9][10][11][12] Owing to the high conductivity (e.g., >10 4 S cm −1 for Ti 3 C 2 T x ), large specific area, and high transmittance, 2D MXene nanosheets have been widely used as transparent electrodes to construct MXene-related photodetectors through solution-processable approaches. [13,14] More importantly, the MXenes possess an adjustable work function in a wide range from 1.6 to 5.8 eV, depending on the various surface functional A high Schottky barrier height (Φ B ) is one of the essential prerequisites for achieving high-performance self-powered Schottky-barrier diode (SBD)based photodetector. The Φ B value is predominantly determined by the metal function and interface quality of the metal/semiconductor contact. 2D MXenes with adjustable work functions and dangling bond-free properties are promising building blocks for constructing self-powered SBD with high Φ B . Herein, a novel Ti 3 C 2 T x MXene/Si hexagonal microhole array (SiHMA) van der Waals SBD is developed for the first time via a feasible solution process. Significantly, the device possesses a large Φ B up to ≈1.07 eV, which is among the highest for the Si-based SBD. In consequence, the Ti 3 C 2 T x /SiHMA SBD yields a large responsivity up to 302 mA W −1 and detectivity as high as 5.4 × 10 13 Jones in a self-powered model, surpassing the performance of most 2D material/Si photodiodes reported to date. Furthermore, it is demonstrated that featured and reliable fingertip photoplethysmogram (PPG) signals can be detected using the self-powered SBD, enabling us to further accurately extract the heart rate (HR), and blood pressures (BP) using the PPG-only method. This work paves the way for the construction of high-performance MXenesbased self-powered SBDs for health monitoring.