Synthesis and Characterization of Superconducting β-Mo2N Crystalline Phase on a Si Substrate: An Application of Pulsed Laser Deposition to Nitride Chemistry

Molybdenum nitride β-Mo 2 N 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 Mo 2 N 0.85 by calibrated X-ray photoelectron spectroscopy. These results demonstrated that the well-crystallized tetragonal-phase β-Mo 2 N was synthesized by deposition, rather than a cubic γ-phase with randomly distributed nitrogen vacancies. The nitride β-Mo 2 N was superconducting below 5.2 K.