Elastocapillarity-driven 2D nano-switches enable zeptoliter-scale liquid encapsulation

Design and operation of the nanoswitches

We designed nanochannels using van der Waals assembly of mechanically exfoliated crystals of graphite (Gr), hexagonal boron nitride (hBN) or tungsten disulphide (WS₂) transferred onto a silicon substrate with a thermal oxide layer (SiO₂). The graphite crystal (thickness: \(h\sim 10-20\,{{\mbox{nm}}}\)) was patterned into stripes using electron beam lithography and reactive ion etching to define spacers. The channel width (\(w=400-1000\,{{\mbox{nm}}}\)) and the top crystal thickness (\(t=10-40\,{{\mbox{nm}}}\)) defined the top channel wall…