Local Electronic Structure and UV Electroluminescence of n-ZnO:N/p-GaN Heterojunction LEDs Grown by Remote Plasma Atomic Layer Deposition

Nitrogen-doped ZnO (ZnO:N) films have been prepared by remote plasma atomic layer deposition (RP-ALD) and treated by rapid thermal annealing (RTA) in oxygen atmosphere. The local electronic structures of the (ZnO:N) films were investigated by X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge spectroscopy (XANES) at the O K-edge. The XPS reveals the presence of the Zn-N bond in the ZnO:N films, indicating that partial amounts of oxygen sites are occupied by nitrogen species. This is correspondent with the decrease of electron concentration in ZnO:N films with the nitrogen doping concentration, as indicated by the Hall effect measurement. The RP-ALD technique was applied to fabricate the n-type ZnO:N/p-type GaN heterojunction LEDs. Dominant ultraviolet electroluminescence at 371 nm from the ZnO:N layer was observed at room temperature.