8152 – GaN/NbN Epitaxial Semiconductor/Superconductor Heterostructures

The proposed invention represents a method to grow and integrate niobium nitride (NbN)-based superconductors with the wide-bandgap family of semiconductors – silicon carbide, gallium nitride (GaN) and aluminum gallium nitride (AlGaN) – by molecular beam epitaxy. Direct epitaxial growth of high-quality semiconductor heterostructures and devices on crystalline nitride superconductors opens up the possibility of combining the macroscopic quantum effects of superconductors with the electronic, photonic, and piezoelectric properties of the group III/nitride semiconductor family.




The proposed method of manufacturing semiconductor-superconductor crystal structure allows GaN to be grown directly onto a crystal of niobium nitride (NbN), a proven superconductor material used in quantum communications, astronomy, and a host of other applications. The method for combining the two materials – molecular beam epitaxy (MBE), essentially spray painting of gallium and nitrogen atoms onto the NBN in a vacuum environment – creates an extremely clean interface and is key to the success of the novel structure.

The specialized nitride MBE system includes an electron beam evaporator source, which “melts” the niobium – which has a melting point of around 4,500 degrees – but not the crucible it’s in. Atoms of niobium are deposited onto a silicon carbide wafer, and the GaN semiconductor layers are then grown on top of that, also by MBE. This method allows to overcome the temperature limitations of conventional sources and brings high-melting-point, refractory transition metals like niobium and tantalum into the picture. It is possible now to combine the macroscopic quantum effects of superconductors with the rich electronic and photonic properties of group III-nitride semiconductors.

Potential Applications

  • Diodes can be used as microwave mixers, in RF superconducting quantum interference device (rf SQUID) readout electronics, as a video detector of high-frequency radiation
  • Majorana zero-modes for braiding-based topologically protected quantum computation
  • Rashba-driven topological insulators

Contact Information

Name: Martin Teschl

Email: mt439@cornell.edu

Phone: (607) 254-4454