Foster STEM Communication & Public Engagement

CAREER: Enhanced Ferroelastic Toughening in Electroceramic Composites through Microstructural Coupling

National Science Foundation Award #1654182
Jessica Krogstad
Materials Science and Engineering
Dates: June 1, 2017–May 31, 2022 (Estimated)

NON-TECHNICAL DESCRIPTION: Specific bonding configurations in ceramic materials enable unique functionalities in a wide range of advanced applications, including superconductive wires in supercomputers, precise gas sensors in automotive exhaust and tilt sensors in consumer electronics. However, these same atomic bonds are also the responsible for the characteristic brittle failure behavior of ceramics. This research is generating new perspectives on fundamental mechanical responses within a class of electrical ceramics necessary to enhance durability without sacrificing electrical performance. By coupling these insights with processing science, this project is accelerating the development of new electroceramic materials and material systems that may drastically expand the existing limits of performance and durability. Through a variety of education and outreach activities, this project also promotes engagement and retention of traditionally underrepresented students. These activities include a high school summer camp for young women interested in material science, integration of industrially relevant, computational tools into undergraduate courses, and expanded mentorship of female graduate students within the college of engineering.

TECHNICAL DETAILS: This project is experimentally establishing a fundamental relationship between otherwise stochastic morphological features and intrinsic toughening mechanism in order to systematically design highly durable, ferroelastic/ferroelectric functional composites. Ferroelastic switching is one of a limited number of intrinsic toughening mechanisms available for advanced ceramics, yet it is not fully utilized due to the largely uncharacterized relationship between localized morphological features, efficient activation of domain nucleation and motion, and resultant improvements in toughness. By bridging this gap using in situ microscopy and targeted micromechanical probes, this research is providing the foundation for accelerated physics-based design of more durable ceramic composite systems. Finally, the state of the art characterization and processing methods used in this project in combination with a data-driven integrated computational materials engineering perspective is enhancing the overall development of graduate students, preparing them for an ever more digitally-reliant materials science industry.

CAREER: Transforming Electronic Devices Using Two-dimensional Materials and Ferroelectric Metal Oxides

National Science Foundation Award #1653241
Wenjuan Zhu
Electrical and Computer Engineering
Project Dates: February 1, 2017–January 31, 2022 (Estimated)

Nontechnical description: Next generation information technology is driving the quest for energy efficient electronic devices to process unprecedented amounts of data in real time and in an energy- and cost-efficient manner. In this program, the principle investigator (PI) is planning to create and evaluate novel energy efficient electronic devices based on a new hybrid material platform consisting of two-dimensional (2D) materials (mono-/di-chalcogenides and graphene) and ferroelectric metal oxides (doped hafnium and zirconium oxides). The ferroelectric metal oxides provide programmable and non-volatile doping in 2D materials, while the atomically thin bodies in 2D materials enable strong electrostatic control over the channel by the ferroelectric metal oxides. Most previous research on 2D/ferroelectric hybrid materials has focused on traditional perovskite ferroelectric materials. This proposed work will undertake the first systematic study of 2D materials on newly discovered ferroelectric hafnium and zirconium oxides, which have the advantages of excellent scalability, high coercive field, and full compatibility with complementary metal oxide semiconductor (CMOS) technology. The PI's team will investigate the synthesis of this new hybrid material platform and create ultra-low power logic, memory, and analog devices based on these materials. The low power logic and memory devices based on these materials will be essential for mobile devices, medical implantable devices, wearable electronics, and large data centers. Analog classifiers based on these materials will enable high speed and low power signal processing and image recognition systems. 3D integration of these low power 2D ferroelectric devices with high speed silicon circuits will result in next-generation highly parallel and ultra-low power systems to support "Big Data" applications such as the Internet of Things and social media. The PI will integrate research and teaching by creating a new graduate/undergraduate course on 2D materials to train the next generation workforce in nanoelectronics. The PI will establish several outreach activities including a new "Little Einstein" science education program for elementary students to cultivate young minds at an early age to respect and embrace a career in science and technology. The PI will also establish a "Girls Go Tech" program for middle school girls to promote enrollment of female students in science and engineering programs.

Technical description: The objective of the proposed research is to establish the foundation for a new research direction: nanoelectronics based on 2D/ferroelectric metal oxides hybrid material platform. The PI's team will synthesize and characterize 2D/ferroelectric metal oxide stacks, seeking fundamental understanding of the ferroelectric phase transition in metal oxides with 2D materials as substrate/capping layers. The team will also utilize these materials to create energy efficient logic, memory, and analog devices. Specifically, the team will create and evaluate novel 2D ferroelectric tunneling field effect transistors (2D Fe-TFETs) to serve as ultra-low power logic; will investigate 2D ferroelectric hafnium oxide transistors (2D FHOT) to implement highly energy efficient, scalable, and durable ferroelectric random access memory (FRAM); will create embedded-gate graphene ferroelectric transistors (EGGFTs) to realize highly energy-efficient, extremely compact, and non-volatile analog classifiers. These devices will then be stacked layer-by-layer to realize 3D monolithic integration. This research will elucidate the device physics and evaluate the potential of these devices for future semiconductor technology. The resulting 3D integrated system will provide the hardware foundation for new circuit and architecture designs. This research is potentially transformative as it may unlock new lines of research and development in energy efficient devices, circuits, and architectures with a broad range of emerging applications from wearable electronics and implantable medical devices to data centers.