Papers by Author: Xiu Jian Chou

Abstract: Pb0.97La0.02(Zr0.95Ti0.05)O3 antiferroelectric thick films were prepared on platinized silicon substrates by sol–gel methods. Films showed polycrystalline perovskite structure with a strong (100) preferred orientation. The antiferroelectric nature of the films was confirmed by the double hysteresis behaviors versus applied field. The temperature dependence of dielectric constant and loss displayed the Curie temperature was 225oC.The current caused by the polarization and depolarization of polar was detected at coupling application of electric field and temperature. The phase transition characterization could be effectively adjusted by electric field and temperature.

Abstract: Piezoelectric thin films cantilevers with a central Si mass are designed for harvesting vibration energy applications. Through the theoretic analyzer and MATLAB simulation, the displacement, resonance frequency and maximum stress dependent of the different structure parameters of micro-power device are obtained. It shows that increasing the quality of mass and the length of microcantilever, decreasing the width and thickness of microcantilever can realize the low-frequency resonance and maximum power in actual design. The static and mode analysis of the theory model are done by using Ansys 11.0. The results can provide guidance for the design and fabrication process of micro power generator.

Abstract: (Pb,La)(Zr,Ti)O₃ antiferroelectric thick films were prepared on Pt (111)/ Ti/SiO₂/Si (100) substrates by a sol-gel process. The effects of single annealing and multistep annealing on the structures and electric properties of the films were investigated. The crystal orientation and structure of the antiferroelectric thick films were studied. The thick films by multistep annealing have higher (100)-preferred orientation than them by single annealing. The surface of the films was more smooth, compact and uniform by single annealing. The antiferroelectric nature of the (Pb,La)(Zr,Ti)O₃ antiferroelectric thick films by various sintering procedures was demonstrated by P(polarization)-E(electric field) and C(capactitance)-E(electric field). The temperature dependent of the dielectric constant and loss was measured under the frequency 1, 10, and 100 kHz and comparing with traditional signal annealing, the films have phase transition from antiferroelectric state to paraelectric state by multistep annealing.

Abstract: By the sol-gel process, Pb_0.97La_0.02(Zr_0.95Ti_0.05)O₃ (PLZT) antiferroelectric (AFE) thin films with different thicknesses were successfully deposited on Pt(111)/Ti/SiO₂/Si(100) substrates. The phase structure of the PLZT antiferroelectric thin films was studied by X-ray diffraction (XRD) analyses. The electric field-induced AFE-FE phase transformation behavior of the PLZT thin films，was examined by polarization versus field (P-E) and relative permittivity versus field (C-E) measurements, with priority focused on thickness-dependent phase switching field. The current by the polarization and depolarization of polar in the PLZT films was measured through current density-electric field (J-E) measurement. With the increase of film thickness, the maximum polarization less and less, the maximum current density is increasing.