Detection of electrically formed photosensitive area in Ca-doped BiFeO3 thin films

We report on the visualization of n-p junctions formed by oxygen vacancy movement under the application of an electric field in a Ca-doped BiFeO3 thin film through spatially resolved scanning photocurrent mapping. The photocurrent mapping, in conjunction with the spectroscopic approach, provides clues to local electronic structures and defect levels associated with oxygen vacancies. These observations provide insights into the spatial redistribution of oxygen vacancies in an electric field.