Conductivity and photo-response of amorphous-LaAlO₃/SrTiO₃ (001) grown by on-axis radio-frequency magnetron sputtering

LaAlO3/SrTiO3 (LAO/STO) possesses many novel properties. To pursue its application in future electronic devices, studying of its mass production and controllability by external stimuli are indispensable. Here, we fabricate conducting amorphous-LAO/STO (001) (a-LAO/STO) for the first time by on-axis radio-frequency (RF) magnetron sputtering. The properties of sputtered a-LAO/STO dependent strongly on growth parameters, with low electroconductibility but strong photo-response in samples sputtered at large target-to-substrate distance and/or under high Ar gas pressure. Using X-ray photoelectron spectroscopy (XPS) to investigate the film's stoichiometry, we find that this is related to Al deficiency (Al/La<1) in a-LAO among these samples. Our work demonstrates that sputtering is a feasible method for controllable, large-scale and low-cost fabrication of oxide interfaces.