Black phosphorus field effect transistors stable in harsh conditions via surface engineering

Black phosphorus (BP) has potential for fabricating p-type transistors in ultra-thin 2D-material complementary circuits. However, as the synergetic effect of water and oxygen leads to performance degradation under an ambient atmosphere, it is urgent to develop a passivation strategy for robust stability. Herein, a scalable superhydrophobic passivation layer is designed to improve the stability of BP transistors, which consists of fluoroalkylsilane-coated titanium dioxide (TiO₂) nanoparticles. Due to the superhydrophobic property of the passivation layer, the BP transistors preserve intrinsic performance in extremely wet conditions, including humid air, water, HCl, and KOH. After 28 days in atmospheric conditions, the performance presents only 20% channel current degradation and the device can work even after 60 days. This work not only experimentally demonstrates robust stable BP transistors in harsh conditions but also provides a highly efficient and damage-free strategy to suppress the influence of water adsorption in atmospheric conditions for highly stable 2D materials devices.