  Binary III-N nitride semiconductors with wurtzite crystal structure such as
GaN and AlN have been long used in many practical applications ranging from
optoelectronic to telecommunication. The structurally related ZnGeN2 or ZnSnN2
derived from the parent binary compounds by cation mutation (elemental
substitution) have recently attracted attention, but such ternary nitride
materials are mostly limited to II-IV-N2 compositions. This paper reports on
synthesis and characterization of zinc niobium nitride Zn2NbN3 - a previously
unreported II2-V-N3 ternary nitride semiconductor. The Zn2NbN3 thin films are
synthesized using a single-step adsorption-controlled growth, and a two-step
deposition/annealing method that prevents loss of Zn and N. Measurements
indicate that Zn2NbN3 crystalizes in wurtzite-derived structure, in contrast to
chemically related rocksalt-derived Mg2NbN3 compound synthesized here for
comparison using the two-step method. The estimated wurtzite lattice parameters
are a = 3.36A and c = 5.26A, (c/a = 1.55), and the optical absorption onset is
at 2.1 eV for this cation-disordered Zn2NbN3. For comparison, published
computational studies predict cation-ordered Zn2NbN3 to be a semiconductor with
effective wurtzite c/a = 1.62 and a band gap of 3.5 - 3.6 eV. Overall, this
work expands the wurtzite family of nitride semiconductors, and suggests that
other ternary nitrides should be possible to synthesize
