Fermi‐Level Pinning‐Free 2D Hybrid MXene/ β ‐Ga 2 O 3 van der Waals Polarization‐Sensitive Schottky Photodiodes

ABSTRACT Metal‐semiconductor (MS) interface plays a crucial role in electronic and optoelectronic devices, where Fermi‐level (FL) pinning is the primary proposal for the formation of a Schottky barrier. The concerned carrier transport would be seriously influenced by the electronic states and defects at the MS interface. Traditional metal electrodes always introduce a severe FL pinning effect, which limits device performance. Thus, introducing an MS interface with low contact resistance and weak FL pinning is desired. Here, a high‐performance MXene/ β‐ Ga 2 O 3 van der Waals (vdW) Schottky photodiode is introduced. The exceptional MXene/ β‐ Ga 2 O 3 interface alleviates FL pinning by achieving a pinning factor of 0.995, remarkably close to the Schottky‐Mott limit. In this case, the rectification ratio of MXene/ β‐ Ga 2 O 3 vdW Schottky photodiode approaches ∼10 9 with an ultra‐low reverse leak current of ∼10 −12 A. The proposed photodiode exhibits standout self‐powered photoresponse, its rise and decay times are 0.27 and 0.29 ms, respectively, and responsivity is 125.1 mA/W. Notably, the device exhibits polarization‐sensitive photodetection with a linear dichroic ratio of 7.1 at zero bias. These findings underscore the promise of MXene/ β‐ Ga 2 O 3 vdW Schottky photodiode for next‐generation deep ultraviolet (DUV) optoelectronic technologies, offering superior performance and potential applications in the Internet of Things and energy‐efficient systems.