1,720,969 research outputs found
Investigation of Fatigue Characteristics of Domain in Pb(Zr0.52Ti0.48)O3(PZT) Thin Films using Atomic Force Microscopy(AFM)
No full textFabrication and characterization of thin and smooth PZT nano films
No full text학위논문(박사) - 한국과학기술원 : 재료공학과, 2002.8, [ ix, 155 p. ]한국과학기술원 : 재료공학과
Characterization of the Property Degradation of PZT Thin Films with Thickness
No full textThe property degradation of lead zirconate titanate (PZT) thin films with thickness was investigated. PZT thin films were fabricated under the optimum established conditions. PZT thin films with a thickness of less than 30 nm did not show the perovskite phase. When considering the thickness of the reacted layer between the PZT thin film and the Pt bottom electrode of about 10 nm in thickness, a thickness of 30 nm was considerable compared to the critical thickness (18 nm) over which PZT shows ferroelectricity. The degree of (001) orientation increased as the thickness increased due to the competition between the effect of the surface energy and that of the lattice mismatch with Pt(111). The degradation of the ferroelectricity with increasing PZT thickness was investigated. PZT thin films with a thickness of less than 30 nm did not show ferroelectric properties. The remnant polarization decreased and the coercive field increased as the PZT thickness decreased. We speculate that the increase in the residual stress and the decrease in the grain size with decreasing film thickness were the major factors in the decrease in the remnant polarization while the increase in the contribution of the low dielectric layer between the PZT and the bottom electrode contributed most to the increase in the coercive field. The leaky behavior of PZT thin films with thicknesses of less than 30 nm appeared to be due to the existence of metallic Pb at the PZT grain boundary, as observed by X-ray photoelectron spectroscopy
Fabrication and investigation of ultrathin, and smooth Pb(Zr,Ti)O(3) films for miniaturization of microelectronic devices
No full textPb(Zr0.52Ti0.48)O-3 (PZT) thin films were fabricated on Pt(111)/TiOx/SiO2/Si substrates at 375 degreesC by radio frequency magnetron sputtering. A mixture of (110) and (100) orientations was found in all the PZT thin films. However, the in-plane grain size increased with an increase in film thickness, all films had smooth surfaces, and the root mean square roughness of the PZT films was in the range of 1-1.5 nm. As the film thickness increased, a decrease in residual stress and volume density of the PZT films was observed. PZT films become poorly crystallized with a decrease in film thickness. The magnitude of the maximum displacement from atomic force microscopy in local piezoresponse hysteresis mode increased from 187.25+/-9.363 in 40 nm to 418.5+/-20.925 in 152 nm. We suggest that the degradation in piezoelectric properties with a decrease in film thickness resulted from degradation of the crystallinity observed using transmission electron microscopy analysis, size effects derived from the grain size, and the residual stress evaluated using a laser reflectance method. (C) 2002 American Institute of Physics.This work was supported by the Ministry of Education (Brain Korea 21), the Ministry of Science and Technology (21C Frontier R&D Program), the Korean Science and Engineering
Foundation (The Study of the Single Transistor
FRAM), and the Institute of Information Technology Assessment (IITA) (No. 2001-163-2).
Binder-free printed PEDOT wearable sensors on everyday fabrics using oxidative chemical vapor deposition
No full textPolymeric sensors on fabrics have vast potential toward the development of versatile applications, particularly when the ready-made wearable or fabric can be directly coated. However, traditional coating approaches, such as solution-based methods, have limitations in achieving uniform and thin films because of the poor surface wettability of fabrics. Herein, to realize a uniform poly(3,4-ethylenedioxythiophene) (PEDOT) layer on various everyday fabrics, we use oxidative chemical vapor deposition (oCVD). The oCVD technique is a unique method capable of forming patterned polymer films with controllable thicknesses while maintaining the inherent advantages of fabrics, such as exceptional mechanical stability and breathability. Utilizing the superior characteristics of oCVD PEDOT, we succeed in fabricating blood pressure- and respiratory rate-monitoring sensors by directly depositing and patterning PEDOT on commercially available disposable gloves and masks, respectively. Those results are expected to pave efficient and facile ways for skin-compatible and affordable sensors for personal health care monitoring.
Nanoscale piezoresponse of 70 nm poly(vinylidene fluoride-trifluoro-ethylene) films annealed at different temperatures
No full textIn order to characterize the piezoelectric properties of 70 nm thick poly(vinylidene fluoride-trifluoroethylene), P(VDF-TrFE), films grown by a spin-coating technique, both nanoscale manipulation and polarization switching were studied using piezoresponse force Microscopy (PFM). We varied the annealing, temperature from 75 degrees C to 145 degrees C and achieved a high-quality 70 nm P(VDF-TrFE) film annealed at the temperature of 95 degrees C. Ferroelecrtic domains and their properties were confirmed using X-ray diffraction, grazing incidence reflection absorption Fourier, Transform Infrared (GIRA-FTIR) and PFM analysis. The ferroelectric domains in the film were homogeneously switchable below 5 V with a remnant d(33) of 14.9 pm/V. This offers out rationale for a promise in energy harvesting and switchability would be good for plastic electronics. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
The Effect of Bias Stress on the Performance of Amorphous InAlZnO-Based Thin Film Transistors
No full textIn amorphous InAlZnO (a-IAZO), the addition of the third cation of Al further slows the crystallization kinetics of In2O3 and enhances amorphous phase stability, compared to the binary cation system of InZnO. In addition, substantially high carrier mobilities of a-IAZO are obtained, in its unannealed state: Hall mobility of 30-50 cm(2)/Vs at a high carrier density regime (>similar to 10(18)/cm(3)) and thin film transistor (TFT) field effect mobility of similar to 8-15 cm(2)/Vs at a low carrier density regime (<similar to 10(16)/cm(3)). Gate bias stress stability of IAZO TFTs is investigated with positive and negative gate biases over time. Because of the channel depletion of n-type IAZO when negative gate bias is applied, no performance instabilities were identified. However, with positive gate bias stress (PBS) conditions (30 V), the threshold voltage (V-T) shifts towards higher voltages during the initial 100 s and then no significant changes in V-T are observed during the remaining time, over 10(5) s of the dependent measurements. The TFT field effect mobility shows a similar trend: increases from 7.64 cm(2)/Vs to 11.74 cm(2)/Vs within the first 100 s and then is saturated. It is identified that the PBS-induced device parameter variations are attributed to an increase and saturation of trap density at the channel/dielectric interface.
Preparation and characterization of (Sr1-xTix)O3 and (Ba1-xSrx)TiO3 thin films using ECR plasma assisted MOCVD
No full textThe Effect of Buffer Layer on the Fabrication and Characteristics of Ferroelectric Thin Films
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