MoS₂/MoO_x Heterojunction Diode Enabled via O₂ Plasma Oxidation for Photon-Controlled Rectification and Nonvolatile Memory Applications

Two-dimensional transition metal dichalcogenide (TMD) semiconductor-oxide systems have a wide range of applications in fields such as interface engineering, active catalysis, and photodetection. Particularly, owing to the energy band alignment, MoS 2 /MoO x heterojunctions show a rectifying behavior, holding promise to become a building block for device construction. However, on the one hand, the efficient preparation of MoS 2 /MoO x heterojunctions remains challenging. On the other hand, previously reported MoS 2 /MoO x heterojunction diodes typically exhibit a low rectification ratio (<10 3 ) and can only perform a specific function. Here, we report a high-performance MoS 2 /MoO x vertical heterojunction diode fabricated via efficient O 2 plasma oxidation, which exhibits an ideality factor of 1.37 and a high rectification ratio of 2.4 × 10 4, surpassing the performance of previously reported devices. Utilizing this heterojunction diode, we subsequently develop a multifunctional photon-controlled diode, which can switch from a cutoff state to a rectifying state under illumination and possesses exceptional nonvolatile response and memory characteristics (nonvolatile responsivity of ∼10 7 A/W, specific detectivity of ∼10 15 Jones, and retention time exceeding 10 4 s). Our work provides a promising strategy for constructing MoS 2 /MoO x heterojunctions and advancing their application in high-performance, multifunctional devices.