Advances in Dielectric Materials and Electronic Devices: On Demand Oral Presentations
Sponsored by: ACerS Electronics Division
Program Organizers: Amar Bhalla, University of Texas; Ruyan Guo, University of Texas at San Antonio; Rick Ubic, Boise State University; Matjaž Spreitzer, Jožef Stefan Institute
Friday 8:00 AM
October 22, 2021
Room: On-Demand Room 5
Location: MS&T On Demand
Session Chair: Matjaz Spreitzer, Jozef Stefan Institute
Invited
Neural Networks, Graph Approach and Fractals Application on Electronics Parameters Determination and Prediction in Perovskite Ceramics: Vojislav Mitic1; Ivana Radovic2; Branislav Randjelovic1; Srdjan Ribar3; Cristine Serpa4; Ivana Ilic1; Aleksandar Stajcic5; Vesna Paunovic1; Branislav Vlahovic6; 1University of Nis; 2University of Belgrade, ‘VINČA’ Institute of Nuclear Sciences – National Institute of the Republic of Serbia; 3University of Belgrade; 4ISEL - Instituto Superior de Engenharia de Lisboa do Instituto Politécnico de Lisboa; 5University of Belgrade, Center of Microelectronic Technologies, Institute of Chemistry, Technology and Metallurgy – National Institute of the Republic of Serbia; 6North Carolina Central University (NCCU)
We modified BaTiO3 and applied fractal nature analysis to connect grain size, pore surface and particles’ Brownian motions with measured dielectric properties. The fractal analysis idea is inspired by self-similarity in nature biosystems, where the chaotic structures could be controlled by recognized geometry structure or just to have disorder controlled towards the order. Fractal regression curve can be used for the reconstruction of the bacteria and viruses (such as COVID-19) motion; trajectories of the virus motion could be obtained. Another approach to calculate properties at the grain boundary based on the bulk sample measurements was employment of artificial neural networks. Their biomimetic ability allows the usage of very simple computer operations solving complex mathematical problems. As the third method, we applied graph theory, developing 1D, 2D and 3D cases, calculating values at grain boundary via matrix count. At the end, the main goal is to establish fractal electronic neural networks.
Effect of Fluoride Substitution on the Morphology and Electrical Properties of Dielectric Storage Material: Narsingh Singh1; Laxman Singh2; Dinesh Prajapati2; Narayan Singh2; Fow-Sen Choa1; Bradley Arnold1; Kamdeo Mandal2; Lisa Kelly1; Atendra Kumar2; 1University of Maryland Baltimore County; 2Indian Institute of Technology, BHU
Modification in the design and production of a low cost material with proven process provides a pathway for high energy density dielectric energy storage. Barium titanate and Barium strontium titanate have been proven as commercial materials for their wide applications in variety of devices and components most notably for memory applications. These materials have been studied for their processing, electrical and dielectric properties. These are ferroelectric and unstable showing phase transitions. there is a continuous effort to achieve high dielectric constant and high resistivity at low cost for large scale applications. Fluorine doped barium strontium titanate dielectric material was studied to determine morphological transition and its effect on dielectric properties. Dielectric is highly dependent on processing methods and shows variation with crystallinity of material, processing temperature and cooling conditions during processing. This transition enables possibility of fibers and self-assembled structures for conformal structures for energy storage without decrease in capacitance.
Electrical and Dielectric Behaviour of Li-substituted Potassium Sodium Niobate System: Maryam Azadeh1; Till Froemling1; Ze Xu2; Yixuan Liu2; Ke Wang2; 1TU Darmstadt; 2Tsinghua University
Lead-free Potassium sodium niobate ceramics have been surveyed for the past 70 years because of their excellent ferroelectric properties. However, the defect chemistry of KNN has not been extensively discussed. In this study, for Li-substituted KNN, we have performed an investigation combining microstructural, electrical and electromechanical characterizations to correlate the structure-property. (Na0.52K0.48)NbO3-xLiNbO3 x=0 - 0.8 ceramic powders were obtained by solid-state synthesis route. It is observed that the primary phase is crystallized in the perovskite structure. Besides, to elucidate the electronic behaviour of ceramics, impedance and capacitance have been obtained using conventional impedance spectroscopy at a temperature range of 100-600 °C. The alteration of AC conductivity in response to frequency unveils an Arrhenius-type conductivity behaviour, resulting in activation energy of 0.4–1.6 eV, correlated with single-ionized and doubly-ionized oxygen vacancies. Impedance spectroscopy results in conjunction with ferroelectric properties measurements helped define the defect chemistry and Li role on KNN material systems.
Epitaxial SrTiO3 Thin Films on Semiconductor Substrates: Matjaž Spreitzer1; 1Jožef Stefan Institute
Sub-monolayer control over the growth at silicon-oxide interfaces is a prerequisite for the epitaxial integration of complex oxides with the Si platform, enriching it with a variety of functionalities. However, the control over this integration is hindered by the intense reaction of the constituents. The most suitable buffer material for Si passivation is metallic strontium. When it is overgrown with a layer of SrTiO3 (STO) it can serve as a pseudo-substrate for the integration with functional oxides. In our study, we determined a mechanism for epitaxial integration of STO with reconstructed Sr(1/2 ML)/Si(001) surface using an all-pulsed laser deposition (PLD) technology. A detailed analysis of initial deposition parameters was performed, which enabled us to develop a complete protocol for integration, taking into account the peculiarities of the PLD growth, STO critical thickness, and process thermal budget, in order to kinetically trap the reaction between the constituents.
Structure and Domain Morphology of Quenched Na1/2Bi1/2TiO3-BaTiO3 Piezoceramics
: Andreas Wohninsland1; Ann-Katrin Fetzer1; Hans-Joachim Kleebe1; Lalitha Kodumudi Venkataraman1; 1Technical University of Darmstadt, Germany
Quenching lead-free perovskite-structured (Na1/2Bi1/2)TiO3-based compositions from the sintering temperature is beneficial in widening the operational temperature range of these materials in application. The thermal stresses that develop upon quenching are insignificant to result in fracture, thus establishing practical relevance of this processing strategy1. In this talk, the results of high resolution diffraction and domain-scale imaging (using TEM) will be presented and a correlation is established with the dielectric properties. The morphotropic phase boundary composition (Na1/2Bi1/2)TiO3-6 mole% BaTiO3 with average cubic and rhombohedral distortions transforms to a mixture of rhombohedral and tetragonal phases, upon quenching2. Quenching refines the phase assemblage and promotes a lamellar domain contrast, which directly correlates to the enhanced ferroelectric stability that increases the thermal depolarization temperature2. Current understanding of the mechanisms related to quenching bismuth-based piezoceramics will be outlined. 1M-H. Zhang et al., Appl. Phys. Lett. 2020; 116(26):2629022A-K. Fetzer et al., Open Ceramics. 2021;100077
Comparison of Chemical Treatments for the Modification of VHB 4910’s Mechanical Properties: Isaac Liu1; Hector Medina1; 1Liberty University
Dielectric elastomer (DE) transducers (DET) are the focus of much research and development, due to their great potential to advance the fields of soft robotics and biomimicry. For some applications, an ideal DE material has a low elastic modulus, low viscoelasticity, high dielectric constant, and high electrical breakdown strength. A commonly used acrylic-based material is VHB4910, which exhibits remarkable properties, when compared against other competing DE candidates. However, those properties are somewhat limited to pre-stretched membranes, which entails additional overhead components in order to completely build DETs. Aiming at eliminating the need for pre-stretch, VHB4910 specimens were cross-linked using Trimethylolpropane Trimethylacrylate, with Benzoyl Peroxide and Azobisisobutyronitrile, as initiators. Variation of initiator ratios led to interesting modifications of material properties, such as elastic modulus and the modulus of toughness, of cross-linked versus non-cross-linked specimens. This study could contribute to advancing knowledge that can lead to the development of simpler DET systems.
Direct-writing of Embedded Flexible Sensors for Strain and Temperature Monitoring for Stretchable Applications: Akshay Kakar1; Derrick Banerjee1; Edward Sabolsky1; Konstantinos Sierros1; 1West Virginia University
Flexible sensors have recently become popular in many applications ranging from soft robotics to wearable optoelectronics. Although various fabrication methods have been studied, the embedding of directly printed conductive inks remains largely unexplored. This is crucial for protecting against the environment and providing good adhesion with silicone. Additionally, silver offers a good balance between cost and electrical and thermal conductivity. In this study, we formulated silicone composite silver inks with varying compositions of binder, solvent, dispersant, and surfactant. These inks were evaluated based on their viscosity, surface tension, and electrical conductivity. The optimum composition was then used for embedding flexible sensors in silicone. The direct ink writing method was used to lay the bottom layer of silicone, followed by direct-writing the strain gauge and thermomechanical sensor designs. The sensors were then embedded under the second layer of silicone. The efficacy of these sensors was evaluated based on their electromechanical performance.