Synthesis and characterization of superconducting β-Mo2N crystalline phase on a Si substrate:: An application of pulsed laser deposition to nitride chemistry

Molybdenum nitride beta-Mo2N was synthesized on Si substrates by pulsed laser deposition of molybdenum metal under nitrogen radical irradiation. X-ray diffraction studies using a multiaxes diffractometer revealed that the crystal phase had a tetragonal structure uniaxially oriented with (100) planes parallel to the substrate surface. The composition was determined to be Mo2N0.85 by calibrated X-ray photoelectron spectroscopy. These results demonstrated that the well-crystallized tetragonal-phase beta-Mo2N was synthesized by deposition, rather than a cubic gamma-phase with randomly distributed nitrogen vacancies. The nitride beta-Mo2N was superconducting below 5.2 K.