Local structural changes induced by ion bombardment in magnetron sputtered ZnO: Al films: Raman, XPS, and XAS study

Abstract Negative oxygen (O − ) ions in the sputter deposition of oxides play a non-negligible role in determining their structures as well as physical properties. Knowledge of bombardment by O − ions induced local disorder in magnetron sputtered ZnO: Al (AZO) films is of fundamental interesting whereas that is currently limited. Here we report our initial results of the local structural changes characterized by a combination of Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS). The bombardment conditions during the film deposition was varied through changing the discharge voltage (i.e., | V d | = 80–220 V) and the substrate positions (i.e., center or erosion region of the target). We found that highly-energetic O − ions bombardment induced a coexistence of various point defects such as oxygen vacancies (V O ), oxygen interstitials (O i ), and zinc interstitials (Zn i ). The concentration of these defects and thus the local disorder can be noticeably reduced through decreasing the | V d | down to a sufficient low level. These results can be used to further optimize the growth processes to achieve the ZnO-based and related thin films with a high structural order.