Ding Aili

Electrical and Pyroelectric Properties of Sol-Gel Derived (Pb, Ca)TiO3 Thin Films with Various Orientations

(Pb0.76Ca0.24)TiO3 (PCT) thin films with various orientations were grown on Pt/Ti/SiO2/Si substrates by using a sol-gel process and by controlling the temperature of heat-treatment. The PCT thin films with (100) and random orientation showed well-saturated hysteresis loops at an applied field of 800 kV/cm, with remanent polarization and coercive electric field of 23.6 μC/cm2 and 225 kV/cm, 17.8 μC/cm2 and 195 kV/cm, respectively. For highly (100)- and random-oriented PCT films, the dielectric constant and dielectric loss values of these films are 121 and 0.016, 121 and 0.024 at 1 kHz, respectively. The pyroelectric coefficients p of the PCT thin films are measured by a dynamic technique. At room temperature, the p values and figures of merits of the highly (100)- and random-oriented PCT films are 185 μC/m2K and 1.79×10−5Pa−0.5, 176 μC/m2K and 1.39×10−5Pa−0.5, respectively.

Growth of Zinc Oxide Thornballs by a Novel Method

Thornballs of zinc oxide (ZnO) is firstly synthesized by a simple solid vapour deposition process under lead oxide (PbO) atmosphere. The micro-thornballs were constituted by numerous needles, which extend outwards in all directions symmetrically. The balls have the dimensions of 120 μm in diameter, while the average diameter of the needles was about 100–200 nm. The needles on the balls grow along the 0001 orientation and have gradient cross-sectional radii. Control experiments proved that PbO plays an important role in the growth. The excitation-emission measurement exhibits that the synthesized ZnO thornballs possess intensive photoluminescence property, which provides the evidence that PbO does not deteriorate the optical properties of ZnO thornballs.

Effects of powder characteristics on the properties of PZT thick films fabricated by a 0–3 composite method

Abstract PZT thick films up to 20μm have been prepared from a 0–3 composite method. The effects of powder characteristics on the microstructure and electric properties of the film have been examined and evaluated. The powder characteristics is found to be of importance in determining dielectric and ferroelectric parameters. PZT thick films made from amorphous PZT fine powders have good electric properties. For PZT(40/60) and PZT(53/47) films, the Pr, Ec, and /varepsilonr are 23.5 and 19.5/varepsilonC/cm2, 48 and 29kV/cm, 680 and 950, respectively.