Simple fabrication method for atomically-thin crystal devices with polymer passivation

Among various candidates of atomically thin crystals, many of them are known to be chemically unstable against elevated temperatures or moisture/oxygen in ambient conditions. Using a mechanical transfer method combined with regular electron-beam lithography, we developed a simple procedure for fabricating the electronic devices based on air-sensitive crystals with polymer passivation. As an example, we show that atomically-thin iron-selenide single crystal maintains its superconductivity after device fabrication, which cannot be realized using the conventional lithography process. This demonstrates that our method offers a new opportunity to investigate the unconventional electrical properties of various atomically-thin air-sensitive crystals.