Synthesis and Characterization of Nitrogen-substituted Nickel Oxide

Nickel monoxide (NiO) displays emergent properties when substituted by other atoms. We present here the synthesis of NiO thin films with low substitution concentrations of oxygen (O) by nitrogen (N), using NO gas-assisted molecular beam epitaxy method. This technique allows us to have a fine control over the N-doping concentration and maintain a high crystallinity in the films. We measure the changes in the electronic structures of these films introduced by N doping, using x-ray absorption and x-ray photoelectron spectroscopies. We identify a strong interaction between the N and Ni atoms. This leads to drastic changes in the electronic states, magnetic ordering, and conductivity of the films.