Self-assembled NaNbO₃-Nb₂O₅ (ferroelectric-semiconductor) heterostructures grown on LaAlO₃ substrates

We deposited NaNbO₃ (NNO)-Nb₂O₅ (NO) self-assembled heterostructures on LaAlO₃ (LAO) to form ferroelectric-semiconductor vertically integrated nanostructures. The NNO component formed as nanorods embedded in a NO matrix. X-ray diffraction confirmed epitaxial growth of both NNO and NO phases. Phase distribution was detected by scanning electron microscopy. The NNO/NO volume ratio was strongly dependent on the deposition temperature due to the volatility of sodium. Piezoelectric force microscopy revealed a good piezoelectric response in the NNO component with a piezoelectric coefficient of D₃₃≈12pm/V, with SrRuO₃ (SRO) acting as bottom electrode. The current-voltage characterization of NNO-NO/SRO-LAO showed a typical diode rectifying behavior.