Figure 1. Domain pattern and macroscopic photovoltaic characterization.

(a) Out-of-plane PFM phase signal indicating a uniform out-of-plane polarization direction and (b) in-plane PFM phase signal showing ±90 phase change for alternative polarization directions in each domains. (c) Macroscopic I-V characteristics under illumination from a 405 nm laser with in-plane electrodes aligned parallel to (red line) and perpendicular to (blue line) the 71° domain walls. (d) Variation of photovoltaic current as function of the angle between light polarization and the in-plane net ferroelectric polarization with in-plane electrodes running parallel (red square dots) and perpendicular (blue circle dots) to domain walls. The continuous black lines are the fitting with Equations 2 and 3 for parallel and perpendicular geometry, respectively.