The effect of nitrogen on the properties of zinc nitride thin films and their conversion into p-ZnO:N films

Abstract Zinc nitride thin films were deposited by magnetron sputtering using ZnN target in plasma containing either N 2 or Ar gases. The rf-power was 100 W and the pressure was 5 mTorr. The properties of the films were examined with thermal treatments up to 550 °C in N 2 and O 2 environments. Films deposited in Ar plasma were opaque and conductive ( ρ ∼ 10 − 1 to 10 − 2 Ω cm, N D ∼ 10 18 to 10 20 cm − 3 ) due to excess of Zn in the structure. After annealing at 400 °C, the films became more stoichiometric, Zn 3 N 2 , and transparent, but further annealing up to 550 °C deteriorated the electrical properties. Films deposited in N 2 plasma were transparent but very resistive even after annealing. Both types of films were converted into p-type ZnO upon oxidation at 400 °C. All thermally treated zinc nitride films exhibited a shoulder in transmittance at around 345 nm which was more profound for the Ar-deposited films and particularly for the oxidized films. Zinc nitride has been found to be a wide band gap material which makes it a potential candidate for transparent optoelectronic devices.