Influence of gas ambient on the synthesis of co-doped ZnO:(Al,N) films for photoelectrochemical water splitting

Al and N co-doped ZnO thin films, ZnO:(Al,N), are synthesized by radio-frequency magnetron sputtering in mixed Ar and N2 and mixed O2 and N2 gas ambient at 100 °C. The ZnO:(Al,N) films deposited in mixed Ar and N2 gas ambient did not incorporate N, whereas ZnO:(Al,N) films grown in mixed O2 and N2 gas ambient showed enhanced N incorporation and crystallinity as compared to ZnO:N thin films grown in the same gas ambient. As a result, ZnO:(Al,N) films grown in mixed O2 and N2 gas ambient showed higher photocurrents than the ZnO:(Al,N) thin films deposited in mixed Ar and N2 gas ambient. Our results indicate that the gas ambient plays an important role in N incorporation and crystallinity control in Al and N co-doped ZnO thin films.