a SEM image of the fabricated Nb−InSb NW−Nb junction device. In this device, the diameter of the InSb NW is about 65 nm, the separation between the two Nb-based contacts is about 110 nm, and the lengths of the InSb NW sections covered by the two Nb-based contacts are about 740 and 680 nm, respectively. See ref. . b Scanning electron microscope image of the device with normal (N) and superconducting (S) contacts. The S contact only covers the right part of the NWs. The underlying gates, numbered 1 to 4, are covered with a dielectric. [Note that gate 1 connects two gates, and gate 4 connects four narrow gates. See ref.