  We report the fabrication of strongly coupled nanohybrid superconducting
junctions using PbS semiconductor nanowires and Pb0.5In0.5 superconducting
electrodes. The maximum supercurrent in the junction reaches up to ~15 \mu A at
0.3 K, which is the highest value ever observed in semiconductor-nanowire-based
superconducting junctions. The observation of microwave-induced constant
voltage steps confirms the existence of genuine Josephson coupling through the
nanowire. Monotonic suppression of the critical current under an external
magnetic field is also in good agreement with the narrow junction model. The
temperature-dependent stochastic distribution of the switching current exhibits
a crossover from phase diffusion to a thermal activation process as the
temperature decreases. These strongly coupled nanohybrid superconducting
junctions would be advantageous to the development of gate-tunable
superconducting quantum information devices.
