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With the current technology having reached the physical limits of size downscaling, efforts need to be made toward the development of new dielectric materials to ensure a low leakage current density that can prevent the tunneling of charges through the dielectric layer. The tunneling of the charges through the dielectric layer is a major factor for degradation in performance as well as higher power consumption. Therefore, recent research has been focused on using materials with high dielectric constants and low leakage characteristics. In this work, we present a detailed study on ZrO2 and Ta2O5 as potential high-k dielectric replacements. MOSCAP devices fabricated using high-k materials have been investigated to study their dielectric properties. Furthermore, a stacked bilayer structure of ZrO2 and Ta2O5 was also investigated to alleviate some of the issues that come along with using high-k dielectrics instead of the more conventional SiO2 dielectric thin film. ZrO2 and Ta2O5 dielectric thin films were successfully fabricated on N++ doped silicon substrates using the electron beam evaporation technique displaying dielectric constants of 20 and 34, respectively. The fabricated MOSCAP devices exhibited leakage current densities as low as 10–8 A/cm2. [ABSTRACT FROM AUTHOR]

One of the ways to mitigate the world energy crisis is to harvest clean and green energy from waste-heat, which is abundant, ubiquitous, and free. Energy harvesting of this waste-heat is one of the most encouraging methods to capture freely accessible electrical energy. Ferroelectric materials can be used to harvest energy for low power electronic devices, as they exhibit switchable polarization, excellent piezoelectric and pyroelectric properties. The most important characteristic of ferroelectric materials, in the context of energy harvesting, is their ability to generate electric power from a time-dependent temperature change. In this work, we grew highly c-axis oriented heterostructures of BaZr0.2Ti0.8O3 (barium zirconium titanate, BZT)/Ba0.7Ca0.3TiO3 (barium calcium titanate, BCT) on SrRuO3 (strontium ruthenate, SRO) and deposited on SrTiO3 (strontium titanate, STO) single crystalline substrate using pulsed laser deposition (PLD) technique. We investigated the structural, electrical, dielectric, and pyroelectric properties of the above-mentioned fabricated heterostructures. The wide range of θ–2θ X-ray diffraction (XRD) patterns only shows (00l) reflection peaks of heterostructures and the substrate which confirmed that the films are highly c-axis oriented. We are also capable to convert the low-grade waste-heat into electrical energy by measuring various temperature-dependent ferroelectric hysteresis loops of our nanostructure films via pyroelectric Ericsson cycles and the structures show an energy conversion density ~ 10,970 kJ/m3 per cycle. These devices exhibit a large pyroelectric current density of ~ 25 mA/m2 with 11.8 °C of temperature fluctuation and the corresponding pyroelectric coefficient of 3425 μC/m2K. Our research findings suggest that these lead-free relaxor-ferroelectric heterostructures might be the potential candidates to harvest electrical energy from waste low-grade thermal energy. [ABSTRACT FROM AUTHOR]

The metal-to-insulator transition (MIT) closest to room temperature of 68–70 °C as shown by vanadium oxide (VO2), compared with other transition metal oxides, makes it a potential candidate for smart window coating. We have successfully fabricated a potential smart window device after the optimum design of a multilayered thin film structure made out of transparent conducting oxide (aluminum doped zinc oxide) and pure VO2 using pulsed laser deposition technique. This comprehensive study is based on two different configurations for multi-layered structure approach, with the intention to reduce the transition temperature, as well as to maintain the MIT properties that would strengthen the potential of the structure to be used for a smart window device. By creating a multi-layered structure, we were able to create a low powered device that can operate less than 15 V that leads to significant decline in the infrared transmission by a magnitude of over 40% and provided sufficient heat to trigger the MIT at a temperature around 60 °C, which is almost 10 °C lower than its bulk counterpart. This finding would positively impact the research on VO2 thin films, not only as smart windows but also for numerous other applications like bolometers, infrared detectors, Mott transistors and many more. [ABSTRACT FROM AUTHOR]