Al–Ge–Al Nanowire Heterostructure: From Single‐Hole Quantum Dot to Josephson Effect

Superconductor–semiconductor–superconductor heterostructures are attractive for both fundamental studies of quantum phenomena in low-dimensional hybrid systems as well future high-performance low power dissipating nanoelectronic and devices. In this work, ultrascaled monolithic Al–Ge–Al nanowire featuring monocrystalline Al leads abrupt metal–semiconductor interfaces used to probe the low-temperature transport intrinsic Ge (i-Ge) dots. particular, demonstrating ability tune dot device from completely insulating, through a single-hole-filling regime, supercurrent resembling Josephson field effect transistor with maximum critical current 10 nA at temperature 390 mK. The realization field-effect high junction transparency provides mechanism study sub-gap mediated by Andreev states. presented results reveal promising Ge-based architecture superconductor–semiconductor devices Majorana zero modes key components computing such gatemons or gate tunable superconducting interference