Institute of High Pressure Physics

Josephson junctions are building blocks of qubits in quantum computers. Researchers from MBE laboratory from our Institute just published a study in Nature Communications Materials showing an important step for the technology of their fabrication. They presented a new approach for growing thin films of superconducting niobium nitride (NbN) on GaN substrates using plasma-assisted molecular beam epitaxy (PAMBE) with indium as a surfactant. The use of indium enabled the growth of NbN thin films with quality suitable for Josephson junction applications. The study demonstrated the world's first NbN/InAlN/NbN Josephson junction fabricated using the MBE method. The junctions achieved a critical current density of 1 kA/cm².

This work shows that MBE technology can be fully exploited for the integration of NbN with group III nitrides, opening the path toward a new class of devices.

The full article A. Lachowski et al. NbN-based Josephson junctions grown by plasma-assisted molecular beam epitaxy Commun Mater 6, 169 (2025) is available at: https://www.nature.com/articles/s43246-025-00891-3