Exfoliating and stacking two-dimensional materials in ultrahigh vacuum
A device-fabrication system keeps freshly exposed interfaces under vacuum while researchers assemble van der Waals heterostructures.
Freshly exfoliated surfaces can pick up contaminants in air and trap them at the interface when two flakes are stacked. This collaboration described a fabrication system that brings exfoliation, transfer and stacking into the same ultrahigh-vacuum environment.
The researchers carried out fabrication at pressures below 5 × 10⁻¹⁰ mbar and tested the system with several samples. Liyuan Zhang at SUSTech contributed to the methodology of the study, published in Review of Scientific Instruments.