摘要:

Very thin films of lead zirconate titanate (PZT) (40/60), 0.26 μ or less, have been prepared on Pt-coated oxidized Si substrates (Pt/Ti/SiO2Si) by a sol-gel process. These films were of high density with fine grains of about 0.2 μm and annealed in the range of 600° to 700°C in oxygen atmosphere. X-ray diffraction patterns taken on this film showed single-phase perovskite-type structure. Pyroelectric and P-E hysteresis curve measurements, as well as measurements of the dielectric constant and loss tangent versus temperature and frequency, were performed. The influence of poling treatment on the dielectric and pyroelectric properties was also investigated, as well as dielectric constants and pyroelectric properties. Dielectric constants and pyroelectric coefficients at room temperature were determined as 1300 and 840, and 68.0 and 10.3 nC/cm2. °C for the poled and unpoled PZT films, respectively. The remanent polarization was 37.8 μC/cm2, and a coercive field was 146 kV/cm at a switching voltage of 16 V peak-to-peak and a frequency of 200 kHz. The remanent polarization and coercive field were found to vary slowly with temperature. The material was also difficult to depole. It is suggested that these films will be suitable for infrared detector applications.

ISSN:1058-4587    

DOI:10.1080/10584589508019369

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A comprehensive theory of the correlation driven metal insulator transition in 1D and 2D strongly correlated electron systems is given. In both the 1D and 2D Hubbard model the metal insulator transition encountered close to half filling is of Pokrovsky-Talapov type. An important consequence of this in the 2D Hubbard model is the break down of the Fermi liquid theory. We also describe in detail the properties of the Pokrovsky-Talapov transition in 2D ferroelectrics.

ISSN:1058-4587    

DOI:10.1080/10584589508019370

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The effects on the capacitance versus voltage (CV) measurement from reducing the film thickness of Symetrix Y-1 ferroelectric material will be presented. The effects on the zero bias capacitance, coercive voltage and coercive electric field as a function of film thickness will also be presented. Obtained CV data was compared to data obtained from hysteresis measurements. The films were fabricated with a spin-on method and the thicknesses of the films were 1741, 2592, 3321, and 4050 Angstroms. The zero voltage capacitance showed a linear relationship as a function of film thickness and a change in the dielectric constant for films greater than 2500 Angstroms. A simple circuit model suggests the enhancement of the dielectric constant for the thin films may be caused by the space charge regions.

ISSN:1058-4587    

DOI:10.1080/10584589508019371

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Fatigue of Pb(Zr0.52Ti0.48)O3(PZT) thin film capacitors under UV light (He-Cd laser, λ=325 nm) was studied. The remnant polarization of PZT films increased upon UV light illumination. The change in the polarization of PZT films upon UV light illumination increased with fatigue cycling. The photoresponse of PZT films under red light (He-Ne laser, λ=633 nm) was also studied. The difference in the steady-state photocurrents of negatively and positively poled PZT films was observed and was found to increase with fatigue cycling. Those results were examined within the framework of polarization screening by defects which is suggested to be responsible for fatigue of PZT films. This leads to a conclusion that more charged defects responsible for fatigue are involved in the fatigue process through internal polarization screening with fatigue cycling.

ISSN:1058-4587    

DOI:10.1080/10584589508019372

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The degradation of ferroelectric properties of PZT films due to plasma damage were investigated. Hysteresis loop and leakage current of PZT films were measured before and after plasma exposure and plasma etching. The damage related defects equivalent to positive charge and neutral traps were introduced into PZT films. Recovery of the plasma damage required annealing at 550°C. The influence of deposition damage of SiO2using TEOS-O3also was investigated.

ISSN:1058-4587    

DOI:10.1080/10584589508019373

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The manifestations of semiconductor depletion and depolarizing effects in switching and fatigue are studied and compared. It is shown that these effects play important but quite different roles in switching. The depletion effect strongly influences the values of the coercive field, Ec, and is responsible for its filmthickness dependence. The depolarizing effect influences significantly other parameters of the hysteresis loops. It is shown that the inverse thickness dependence of Eccan not be attributed to the presence of a non-switching layer. Contribution of the effects in question to fatigue of the loop parameters is discussed.

ISSN:1058-4587    

DOI:10.1080/10584589508019374

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

DCconduction mechanisms in lithium niobate thin films as a function of microstructure have been investigated. Sol-gel synthesis of LiNbO3films on Si and Pt-coated Si substrates produced two different microstructures which caused significant differences in the electrical response of these films todcfields. At high fields, space charge limited conduction dominated in near epitaxial, highly textured LiNbO3films on Pt-coated Si substrates. Current-voltage(I-V)characteristics of polycrystalline LiNbO3films on Si substrates were complex, and there is a strong possibility of Poole-Frenkel emission from shallow traps in these non textured films.

ISSN:1058-4587    

DOI:10.1080/10584589508019375

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Domain behavior based on surface energy and volumetric free energy was discussed in relation to imprint. Surface enery and volumetric free energy result in net free energy, which determines the critical size for domain growth. If a domain size is greater than the critical size, they will grow spontaneously under a constant electric field or even under zero electric field. Sometimes, they can grow to the extent that they dominate reverse domains. This phenomenon appears to be polarization reversal under zero voltage bias. Spontaneous domain growth either under zero electric field or a constant electric field was demonstratred. This phenomenon can be partly a source of asymmetric imprint mechanism.

ISSN:1058-4587    

DOI:10.1080/10584589508019376

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We describe our work on LiNbO3thin films grown on Al2O3-c by rf sputtering. X-ray diffraction shows that we grow single phase, epitaxial films in which the lithium content can be varied. Optical measurements and surface morphology characterization show that the optical loss increases with the surface roughness and that the presence of large crystalline outgrowths is a limiting factor for low loss waveguides.

ISSN:1058-4587    

DOI:10.1080/10584589508019377

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Lead zirconate titanate(PZT) thin films have been grown on Pt/SiO2/Si substrate by DC reactive sputteing using multiple metal target. The experimental conditions to form the PZT phase on Pt substrate and electrical properties were systematically studied by changing the Zr content and substrate temperature. The film deposited at 600°C had (001) preferred orientation and had high dielectric constant. The annealed film at 650°C had high remanent polarization and high fatigue resistance to 109cycles.

ISSN:1058-4587    

DOI:10.1080/10584589508019378

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor