Quaternary nitride system (1−x)ZnGeN2−2xGaN (x = 1/3): disordered wurtzite structure revealed by time-of-flight neutron powder diffraction

Abstract

We have synthesized a fairly stoichiometric fine powder sample of the wurtzitic nitride system Zn1−xGe1−xGa2xN2 (x = 1/3) by the gas-reduction–nitridation method, and identified its crystal structure by the time-of-flight neutron powder diffraction and 71Ga solid-state nuclear magnetic resonance spectroscopy. The obtained neutron diffraction pattern clearly showed the absence of superlattice peaks originating from possible cation-ordered structures, and the Rietveld refinement based on the fully disordered wurtzite phase converged with sufficient reliability. The current results may support our view that the cation disorder is the primary factor for the band-gap reduction attained in the Zn1−xGe1−xGa2xN2 system.