Protective molecular passivation of black phosphorus

Black phosphorus is a fascinating layered material, with extraordinary anisotropic mechanical, optical and electronic properties. However, the sensitivity of black phosphorus to oxygen and moisture poses significant challenges for technological applications of this unique material. Here, we report a viable solution that overcomes degradation of few-layer black phosphorus by passivating the surface with self-assembled monolayers of octadecyltrichlorosilane that provide long-term stability in ambient conditions. Importantly, we show that this treatment does not cause any undesired carrier doping of the bulk channel material, thanks to the emergent hierarchical interface structure. Our approach is compatible with conventional electronic materials processing technologies thus providing an immediate route toward practical applications in black phosphorus devices. Making black phosphorus airtight Black phosphorus is a leading contender among new semiconductors for nanoscale optoelectronics, but its use is impeded by rapid degradation in air. A team of Israeli and US scientists, led by Doron Naveh from Bar Ilan University, has devised an inexpensive and scalable approach for long-term stabilization of black phosphorus, bringing it one step closer to real-world applications. By treating black phosphorus with octadecyltrichlorosilane (OTS), a chemical commonly used in semiconductor processing, Naveh and coworkers were able to produce self-assembled polymer coatings that protect black phosphorus from oxygen and moisture. Importantly, this chemical treatment does not alter the overall electronic properties of black phosphorus nor does it complicate subsequent device fabrication. With this advance, researchers can now stabilize and study black phosphorus devices with relative ease under normal operating conditions.