Effect of low energy ion bombardment on structure and photoluminescence characterization of Al-doped ZnO thin films

Al-doped zinc oxide (AZO) films are prepared by dual ion-beam assisted sputter deposition at room temperature. An assisting argon ion beam (ion energy Ei = 0–300 eV) directly bombards the substrate surface to modify the properties of the AZO films. The effects of assisting ion beam energy on the characteristics of AZO films were investigated based on transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy and photoluminescence measurement. With increasing assisting ion beam bombardment, the crystalline quality of the AZO films was improved and the oxygen vacancies were increased observably. Two red emissions originating from the oxygen vacancies in the films appear at 1.71 and 1.64 eV. This study suggests that wide-band-gap materials could act as effective visible light emitters and ion beam bombardment provides a simple route to synthesize such materials.

► Al-doped ZnO (AZO) thin films were prepared by dual ion-beam sputter deposition.
► By assisting-ion beam bombardment, AZO films have a better c-axis orientation.
► The crystalline quality of AZO films was improved by assisting-ion beam bombardment.
► Two red emissions originate from the oxygen vacancies in the films.