Li-N dual-doped ZnO thin films prepared by an ion beam enhanced deposition method

Li-N dual-doped ZnO films ZnO:(Li,N) with Li doping concentrations of 3 at.%-5 at.% were grown on a glass substrate using an ion beam enhanced deposition (IBED) method. An optimal p-type ZnO:(Li,N) film with the resistivity of 11.4 Ω·cm was obtained by doping 4 at.% of Li and 5 sccm flow ratio of N₂. The ZnO:(Li,N) films exhibited a wurtzite structure and good transmittance in the visible region. The p-type conductive mechanism of ZnO:(Li,N) films are attributed to the Li substitute Zn site (Li_Zn) acceptor. N doping in ZnO can forms the Li_i-N_O complex, which depresses the compensation of Li occupy interstitial site (Li_i) donors for Li_Zn acceptor and helps to achieve p-type ZnO:(Li,N) films. Room temperature photoluminescence measurements indicate that the UV peak (381 nm) is due to the shallow acceptors Li_Zn in the p-type ZnO:(Li,N) films. The band gap of the ZnO:(Li,N) films has a red-shift after p-type doping.