Interfacial self-reaction during atomic layer deposition of Al2O3 on oxidized black phosphorus and improved electrical properties by stable surface chemical structure

We invetigated the interfacial reaction of the between high-k dielectric grown by the atomic layer deposition (ALD) process and exfoliated black phosphorus (BP) as a function of air exposure time. The change in chemical state... [ view full abstract ]

We invetigated the interfacial reaction of the between high-k dielectric grown by the atomic layer deposition (ALD) process and exfoliated black phosphorus (BP) as a function of air exposure time. The change in chemical state and structure analysis on oxidized phosphorus species before and after ALD process were investigated using x-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), Atomic force microscopy (AFM), first-principles DFT calculations, and characteristics of a field-effect transistor (FET) based on BP. We observed that oxidized phosphorus species (PO_x) were significantly reduced during the ALD-Al₂O₃ process. In particular, field effect characteristic of Al₂O₃ on oxidized black phosphorus showed that the enhancing electrical properties (mobilties of ~ 253 cm²V^-1s^-1 and on-off ratios of ~10⁵) at the 1 day of exposure time in BP sample. These results of self-reaction between the ALD-Al₂O₃ process and oxidized BP provide an reduction of oxidized phosphorus species by the ALD reaction process and enhancing electrical characteristics of the oxidized BP FET, even in the air exposure enviroment.