Flexible high energy density capacitors were fabricated by depositing 6 mol. % La-doped anti-ferroelectric PbZrO₃ thin films using chemical solution deposition on ultra-thin metal foil substrates. The integration of a LaNiO₃ buffer layer on the flexible austenitic metal foil substrate resulted in substantial improvements in microstructure uniformity and density of the La-doped PbZrO₃ thin film capacitors. The recoverable energy density and the energy loss of the flexible thin film capacitors were 15.2 ± 0.2 J/cm³ and 4.8 ± 0.2 J/cm³ at 1 MV/cm, respectively. The La-doped PbZrO₃ flexible thin film capacitors showed no noticeable degradation in ferroelectric hysteresis behavior and the energy storage density even after 1000 bending cycles.

BiFeO 3 (BFO) films were processed on BaTiO3 (BTO) buffered (111) Pt/Ti/SiO2/Si substrate by pulsed laser deposition. Improved ferroelectric properties, as well as induced ferromagnetism, were observed by the insertion of a BTO layer for rather thick BFO films (450 nm) deposited at an oxygen pressure of 40 mTorr. Reduced leakage current, coercive field, and increased ferroelectric saturation of BFO/BTO bilayer films were obtained and compared with those of BFO films. In order to better understand the buffer layer effect on the magnetic properties, two thinner (140 and 220 nm) BFO films were also deposited and investigated. Both films showed ferromagnetic hysteresis loops and larger in-plane magnetization than out-of-plane magnetization. By introducing the BTO barrier layer, the remnant and saturated magnetizations were also increased. These results demonstrated not only the interface constraint effect but also a coupling between ferroelectric BTO and magnetic BFO, which deserve further investigation.

Top-contact bottom-gate thin film transistors (TFTs) with zinc-rich indium zinc tin oxide (IZTO) active layer were prepared at room temperature by radio frequency magnetron sputtering. Sintered ceramic target was prepared and used for deposition from oxide powder mixture having the molar ratio of In2O3:ZnO:SnO2 = 2:5:1. Annealing treatment was carried out for as-deposited films at various temperatures to investigate its effect on TFT performances. It was found that annealing treatment at 350 °C for 30 min in air atmosphere yielded the best result, with the high field effect mobility value of 34 cm2/Vs and the minimum subthreshold swing value of 0.12 V/dec. All IZTO thin films were amorphous, even after annealing treatment of up to 350 °C.

Chemical solution-derived anti-ferroelectric (AFE) thin films for energy storage devices were investigated. In order to evaluate dielectric properties(dielectric constant and loss, leakage current density), anti-ferroelectric properties(energy storage density and loss, energy storage efficiency) of anti-ferroelectric thin films with lanthanum (La) as a dopant, ∼1 μm-thick anti-ferroelectric (PbLa)ZrO₃ (PLZO) films as a function of La doping concentration (0 ∼ 6 mol.%) were deposited on Pt/Ti/SiO₂/Si substrate. With the increase of La-doping concentration, the energy storage loss was reduced from ∼8.8 J/cm³ to ∼6.6 J/cm³, and the efficiency was increased from ∼59.2% to ∼80.7%. In terms of the lowest leakage current density, the maximum energy storage performance was observed in La 2 mol.% doped PLZO thin film capacitor with the energy storage density ∼16.9 J/cm³, energy loss ∼8.4 J/cm³ and energy storage efficiency ∼66.8% at an applied electric field ∼1 MV/cm with frequency ∼1 kHz at room temperature.

The magnetic and the electrical properties of CuFe₂O₄/BaTiO₃ thin films grown on highly-textured Pt(111)/TiO₂/SiO₂/Si(100) substrates were studied. Sintered BaTiO₃ and CuFe₂O₄ pellets prepared by the conventional mixed oxide process were used as targets during deposition by using the ion-beam sputtering and the pulsed laser deposition techniques. The film structure is of a bilayer type, where the BaTiO₃ layer lies underneath the CuFe₂O₄ layer. The CuFe₂O₄/BaTiO₃ film stack was then annealed at a temperature between 700 and 750 °C, followed by either FC (fast-cooling) or SC (slow-cooling) treatment. The ferroelectric and the electrical properties were measured using a ferroelectric test system, a digital multimeter, and an impedance analyzer. The Magnetic hysteresis (M-H) behavior at room temperature was measured using a vibration sample magnetometer (VSM), and the maximum saturation magnetization (M _s ) and coercivity (H _c ) values were 700 emu/cm³ and 325 Oe, respectively.