Ferroelectric thin film on a silicon-based pn junction: Coupling photovoltaic properties

PbTiO3 (PTO) thin film was deposited on a Si-based pn-junction to form a ferroelectric-pn junction structure (PTO/pn cell). It exhibits a coupling photovoltaic property. V-oc of the PTO/pn cell is approximately equal to V-oc summation of single pn-junction structure (pn cell) and single PTO films (PTO cell). I-sc and internal quantum efficiency of the PTO/pn cell are much higher than that of the PTO cell. Photovoltaic properties of the PTO/pn cell can be tuned by controlling the direction of the polarization voltage applied on the cell. Reasons for the tuning and enhanced photovoltaic properties are analyzed.