The mechanism of the maximum photovoltage in perovskite oxide heterostructures with the critical thicknessXu He, Kui-juan Jin, Chen Ge, Cong Wang, Hui-bin Lu and Guo-zhen YangEPL, 102 3 (2013) 37007DOI: https://doi.org/10.1209/0295-5075/102/37007