Preparation And Optical Properties Of Lead Zirconate-titanate Nanostructures

Nanostructures are commonly possess special optical, electrical, thermal, magnetic, information storage and transfer, storage and release of energy, and other functions. Because of Lead Zirconate Titanate(PZT for short) has the advantage of high mechanical coupling coefficient, good pyroelectric properties and high curie temperature, which make the PZT is one of the most useful functional ferroelectric piezoelectric materials and the PZT material also has potential applications in the field of memory, transducer, filter, ultrasonic motor and sensor etc. for its excellent ferroelectric capability. In the thesis, the material properties, structure properties, device design and analysis of the nano structure PZT were researched. The details of my work are listed as following:On the basis of DFT(Density Functional Theory), we adopting the method of the building orderly structure model applied the first principles to do theoretical calculation on tetragonal phase structure of PZT. The samples were represented by five orderly structure model: the tetragonal phase structure PbZrx Ti1-xO3(x = 0.125, 0.25, 0.5, 0.75, 0.875). And then we analyzed the energy band structure, dielectric properties and optical performance in detail. The calculating results indicated that with the increasing of x value, the energy band width of the tetragonal phase perovskite type PZT material showed a trend of increase gradually. And we calculated the rhombohedral phase and tetragonal phase PbZr0.5Ti0.5O3 and found that the rhombohedral phase perovskite type PZT has the ability of higher band width of energy band and more stable structure than the tetragonal phase. The tetragonal phase owns the excellent optical performances in the light of ultraviolet. The calculation method provided rich physical information for the study orderly structure model and helped to study macroscopic physical properties later.We successfully prepared through-hole AAO template, and we used the template, adopting the method of glue and stewing to introduce the PZT sol to the through-hole AAO template hole, the prepared sol was forced into the alumina channels by capillary force and vortex force, then through high heat sintering process to form the cubic perovskite phase PZT nanotubes. The results of SEM showed that the aperture size of the PZT nanotubes was uniform and the arrangement aligned. The inside diameter of the PZT nanotube was approximately 50 nm, and the outside diameter was about 75 nm, the length was about 16 microns. The results of FTIR showed that the PZT/AAO composite structure existing obvious absorption peaks and located in the wavelength of 1471.56 cm-1 and 1556.09 cm-1, the absorption intensity of the composite structure was about six times than the pure porous alumina. Base on the Maxwell-Garnett effective medium theory, the enhancement of the absorption intensity stems mainly from PZT dielectric loss characteristics, and the position of the absorption peak depends on the intrinsic absorption of alumina. And then we verified the idea from the infrared spectrum experiments of the barium strontium titanate/AAO nanotube structure.We adopted the traditional two-step anodic oxidation technology and attained the porous AAO template, its size can be adjusted within a certain range. Adopting the template and through RF magnetron sputtering technology, we prepared the nanoscale PZT/AAO composite structure. The composite structure increased the absorption intensity in ultraviolet frequency, broadened the absorption peak, and existed the red shift of absorption peak phenomenon with the increasing of the thickness of the upper PZT. Theoretical analysis showed that the absorption peak of the PZT/AAO nano system is red shift with the increasing of the PZT particles in the volume share, obeyed the effective medium theory; and the observed the absorption of bandwidth broadening phenomenon of PZT/AAO nano composite structure with the increasing of average particle size in the experiments, its essence was the uneven distribution of particle size of PZT particles induced by volume fraction increase impacted on the optical absorption properties and it did not affect the validity of the Maxwell- Garnett effective media theory. And what's more, we based on the Lead zirconate titanate material and designed the Au/PZT/Au composite layer structure and realized multiband terahertz absorption, and adjusted absorption frequency by changing the top metal structure size, this work provided reference to the terahertz absorber. This has great significance to study the optical properties of PZT composite structure and further application development.This thesis analysed and designed the PZT grating structure absorber, optimized the structure parameters through the finite difference time domain method. When the parameters of PZT grating structure: the period was 200 nm, duty ratio was 50% and the height was 200 nm, the absorption rate of the device was higher than 80% in the wavelength between 220 nm and 500 nm. In the meantime, we analysed the absorption characteristics of the PZT gratings structure's absorber, and then explored and designed the preparation technology of PZT nano gratings. And, in order to keep up with the rapid development of nanotechnology research, this paper also adopted the ellipsometer and the fitting model to measure nano structures grating. Results proved that the machine could work well in nondestructive test of nano grating. And verified each other with SEM, under the condition of the incident angle of 60o and the azimuth angle of 75o, the measurement accuracy can be up to 99.97% for the three-dimensional morphology parameters such as key dimension and sidewall angle and so on. This method was significant for the nondestructive test.