An ultra-high vacuum system for fabricating 2D material devices

Atomically thin two-dimensional (2D) materials exhibit a rich set of electronic properties that may impact future electronic and optoelectronic applications. Many 2D materials, however, are prone to degradation in the presence of trace amount of oxygen or water vapor. The study of the intrinsic properties of these 2D materials requires protection from degradation agents during sample fabrication process. To this end, we design and build an ultra-high vacuum (UHV) system, in which the entire sample fabrication is performed under a base pressure lower than 5×10^-10 mbar. We demonstrate the functionality of this UHV fabrication system by fabricating black phosphorus heterostructures completed with electrical contacts and gate electrode for transport measurements.