In-situ shadow-wall deposited tin junctions on selective area grown buffered InAs nanowires

Semiconductor nanowires with superconducting shells have been explored widely for studying one-dimensional electron transport and topological effects at cryogenic temperatures. Scalable fabrication of arbitrary designs of such hybrid nanostructures with clean disorder-free interfaces, can prove useful for building the next generation of fault-tolerant quantum hardware.

In this talk, we demonstrate a completely customizable platform to grow in-plane indium arsenide (InAs) nanowires and subsequently deposit superconductors at predefined positions on the nanowire, without breaking vacuum. The nanowires were grown using chemical beam epitaxy with a selective-area growth (SAG) technique. High aspect ratio dielectric structures that were prefabricated next to the nanowires were used to subsequently shadow-deposit tin (the superconducting shell) at the preferred locations on the nanowire. This enabled the fabrication of high-quality superconductor-semiconductor-superconductor (SNS) junctions with minimal post-processing steps. Transport measurements from the gated SNS devices at millikelvin temperatures demonstrate gate-tunable supercurrent and a clean superconducting gap with a high critical field. This establishes that the in-vacuo method of shadow-depositing superconductors on SAG nanowires as a technique for scalable fabrication of complex hybrid nanostructures, with clean superconductor-semiconductor interfaces.