Insertion of Zn atoms into Cu3N lattice: Structural distortion and modification of electronic properties

Nanocrystalline Cu3NZnx compound films were synthesized using reactive magnetron sputtering of metal targets. Up to a Zn content of 5.44 at.%, the deposits exhibit a satisfactory crystallinity that the X-ray diffraction patterns show distinct (0 0 1) and (0 0 2) reflections characteristic of the intrinsic Cu3N lattice. The slightly enlarged lattice constant suggests insertion of zinc atoms to the center of cells of primitive Cu3N lattice. All the ternary deposits exhibit an n-typed conductivity. Electrical resistivity at room temperature drops by three orders of magnitude with increasing zinc concentration from 0 to 5.44 at.%, and accordingly the activation energy for electrical conduction decreases from 21.9 to 14.1 meV, indicating the presence of shallow donor levels in doped samples. The electronic transport is governed by thermal activation in lightly doped samples, whereas in samples with a zinc concentration of 5.44 at.% or higher it is instead dominated by a hopping mechanism at low temperatures (<50 K).