Physical properties of crystalline NaNbO3 thin film grown on Sr2Nb3O10 nanosheets at low temperatures for piezoelectric energy harvesters

A Sr2Nb3O10 (SN) monolayer deposited on Pt/SiO2/Si (PSS) was employed as the template for the growth of crystalline NaNbO3 (NNO) thin films at low temperatures. The [001]-oriented crystalline NNO film was effectively grown on SN/PSS at 250 degrees C. This NNO film showed a small epsilon(r) of 115, along with good insulating properties with a low leakage-current density (4.5 x 10(-6) A/cm(2) at 0.3 MV/cm). This NNO film displayed a large d(33) of 123 pC/N, which is the largest d(33) value for NNO films to date. Moreover, it shows a very large d(33) x g(33) (14.8 x 10(-12) m(2)/N), which is the figure of merit for the power of piezoelectric energy harvesters (PEHs). The NNO film grown on SN/Ni at 250 degrees C for the fabrication of PEH also demonstrated dielectric and piezoelectric characteristics. The NNO PEH exhibited a high power density (2.1 mu W/mm(3)), indicating that the [001]-oriented NNO film grown on the SN seed layer is a good candidate for PEH. Moreover, this NNO film can be deposited on a polymer substrate and utilized as a future flexible device owing to its very low growth temperature and good physical properties.